Your 3 main points are well-made. A Wondertown must be safe, happy, and Caravanable. Laying out a program for Wonderization, which addresses all these considerations, and others. First, need to be on a large continent to maximize Hoover and Bach. At 4000 BC, will save the game and start exploring my home landmass. Don't use the WorldMap cheat, but have played enough games to get a "feel" for how much dry land there should be on an average M-class planet. By 3000 BC it's obvious whether i'm on an island or a continent, and how large it is. When i know how big my home is, it's easy to estimate how much land is not on my homeland. Learning Horseback Riding early in the game helps the exploration greatly. If there is not enough land, of the right type to build 20 cities, or if there is likely to be a continent larger than mine, will normally start over with a new map.
If i've got a homeland i can work with, then restart at 4000 BC and go for realsies, and now have identified which general direction the Settlers should be expanding my empire. Usually get up to 6 cities quickly, ideally in a ring around the capital. This makes the initial edible area about 14 X 14 squares, so there will certainly be one city near a coalhill, a horseplain, a large forest, or an oilswamp. So one city can become the productionmeister and quickly supply the military units needed for defense and a small army to go and harass the nearest neighbor. Once things are safe, start the second wave of expansion, making the first 6 cities into an inner core which are all linked and insulated from attack. Now there is a group of safe cities.
Settlers from this inner group all found new cities, then build more Settlers. This round of Settlers is the key to the first round of Wonders. Once a city has Temple, a garrisoned unit, and a Settler, then it is eligible to build a Wonder. The Temple and garrison ensure the city will be happy for the 30 - 40 turns it will be making a Wonder. The Settler immediately knocks the population down by 1, and keeps the city from growing too fast for the Temple and garrison to control the town by themselves. Now there is a group of long-term happy cities.
All the while, the wave of non-building Settlers, knowing that they must exist for 30 - 40 turns, have the luxury of time to knock out some difficult developments. Mines in hills, roads in a few key mountains and forests, a project to road/irrigate a swath of plains. Every shieldgrass irrigated lets a square of plainsmen migrate to a forest. Maybe there's a jungle which looks like a citysite, but needs development in nearby squares before it can be founded upon? There is a dedicated corps of engineers ready to tackle big projects. Turn it loose on finalizing the road network, and the inner group of safe and happy cities is now very Caravanable.
Time for Wonders. By this time, all 7 of the Ancient Wonders should be available. Set up a mutual-aid society where one city in the group builds a Wonder, and the others build Caravans. Pound camels into the first builder, which is usually my capital, and if playing as the Babylonians, then it's the Hanging Gardens there. Playing as Egypt, it'd be the Pyramids, etc. Using Caravans to bring the city within 50 shields of completion, will let it build naturally from there, commonly about 5 turns from finishing. When one city in the group achieves a Wonder, it rejoins the Caravan Campaign until the whole group is all Wondered up. The last one to build is normally the group's productionmeister, who has had non-founder Settlers improving its production squares for 30 turns, and thus is now a powerhouse, with some Caravans coming quickly. By this point, the productionmeister can build an Ancient Wonder in 10 - 15 turns.
Later in the game, as the frontier expands and more cities are safe, organizing newly Wonder-eligible cities into groups of 4 works best for me. Small enough a number to be painless when they're all out of play for 30 - 40 turns, and large enough to benefit from a shared Caravan society.
Of the Ancient Wonders, Colossus is the odd man out. Won't build that until a goldmount is located, with a citysite is nearby which can also eat some other high-value squares, like fisheries, gems, and oases. An irrigated oasis means that you get gold for free, and still grow like a normal city. Very important for the Colossus/Copernicus city to grow. Have discarded scenarios where everything else was good, but the homeland didn't have a single goldmount. With luck, the Col/Cop site will be on the other side of the continent as the startsquare, which can enable worthwhile early trade routes, easy and very early, a pittance to begin with but if established in the dawn of time, can pay a steady dividend over a very long period.
When the Col/Cop site is identified, everything in the empire scrambles. Settlers make their way to the site along with some protective military units. Caravans start heading for the site, and Col/Cop is the only reason i would ever disturb a mutual-aid society in progress. If close to discovering the RR, might wish to adjust the rates to forge advances ahead so Col/Cop can be railroaded before founding. Highly lucrative. This city will be thirsty for Caravans for a long time. Slake it. Temple is 1 Caravan. Granary is 1 Caravan and 20 clams. Marketplace is 1 Caravan and 60 clams. A Bank is 2 Caravans and 40 clams, and a University takes 3 Caravans plus 20 clams. Every camel thrown into the Col/Cop is an investment which pays off fast and forever. Don't forget to new-home 3 Caravans and send them trading, which is like forcing other civs to sell you the tin you need to make the bronze you'll later conquer them with.
Among the seven Medieval Wonders, Shakespeare is the odd man out. You're looking for an inland city with the most shieldgrass and river squares. Grow, baby, grow. But the risk with Shakeytown is having a village on a far-flung island turn into Electronics before you were ready for it, and throwing Shakeytown into chaos when the Globe burns down. I'll build Shakespeare's Theater just because it's 20 civscore points, but rarely allow that city to grow like wild. When i get Religion, Shakeytown is the first place to get a Cathedral "just in case".
Among the 7 Modern Wonders the effects are mostly global, except the Hoover Dam. With Bach, it's the reason to only play deep in scenarios starting on a large continent. 20 loosely-packed cities is the minimum to benefit from Bach and Hoover. 30 is better. By the time you can build these two, it shouldn't matter where you build them, since you should have a pervasive defense capability based on Knights by Bach's time and based on MechInfs by Hoover's day. Either one of those units is kryptonite to anything the Barbies can put in the field at the time. And, if you're able to field Knights overseas then no rival civ should be able to land on your shores with Cannons. Same goes for MechInfs and Artillery.
One vexing problem is how to keep rival civs from building a Wonder before you. Anecdotally, may have solved that problem. Not sure if it's a real thing, or just coincidence and thus a mere civperstition, but since i noticed it, the effect has worked consistently. Here's the trick: when you move a Caravan over to help some city build a Bank or Marketplace or what have you, you must momentarily tell that city to build a Wonder. Then you "help build Wonder" and change the city's build back to whatever they were building. The odd thing i noticed is that whatever Wonder you change a city to build briefly, that Wonder is never built by surprise by another civ at a later date.
Again, not sure if this is a real effect of the AI's programming, or if it's just a coincidence that keeps on happening. But since i noticed it and began watching for it, no rival civ has built a Wonder which i previously faux-built. Would love it if someone could prove or disprove this effect.
yes it would be cheating if i was playing to win, but for some months have been running test-bed games to perfect some techniques which require a large-land home. The current one has a continent which runs from Pole to Pole, with just a 1-square water passage between oceans at the top and bottom of the world. The Col/Cop city in this scenario has 3 goldmounts to eat (and 14 plains/grass/river squares) so it's just teeming with trade-arrows. 
