To recap, my answers to (1) and (2a) were:
1. Plow straight through, get the other swords in Kahnawake there by boat. If we keep our forces concentrated we'll be okay. Sending MWs would take a long time for anything but helping to clear out Ulundi.
2a. Cities which only have a few more than their original 9 available: Zimbabwe (12 tiles available to work), Hlobane (9), Tyendenaga (12), Oka (13), Nara (9), Camp Mistic (14), and Panama (12). The other cities either have had a border expansion or have most of their tiles available by overlap (usually by virtue of being in the core of the empire).
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(2b) Where do we need to send the workers?
Well, how big are our cities going to be growing?

I think this is almost a team discussion point, because the amount of effort we need to spend improving tiles depends on how many of them are actually going to be worked. If we're going for an ideal of having every tile worked for maximum benefit, we'll want to work on every tile in every city's 21.
For now, I think the following cities need more than just a touch-up on a square or two, or they will in the future:
* Osaka - Borderline, as I was getting some stuff done there on my turns. Post-Electricity I might consider going back for some irrigation, but for now it need just a few more turns to increase productivity.
* Tokyo - Borderline as well, although when it starts working more tiles after the next interturn, they'll be weak grasslands. It's not completely hurting for help, but some extra worker turns sure would be nice.
* Grand River has a couple of tiles that still need some irrigation.
* Allegheny definitely needs some improvements: the plains squares SW and 2NW of the city both need irrigation. If (when?) Allegheny's borders expand, the extra grass tile near Akwesasne and the mountains could use some benefits. I think Allegheny has enough food production potential (clear that forest and irrigate, maybe?) that mining the mountains and working them is not out of the realm of possibility, but we should finish irrigating plains first.
* Satsuma just needs general improvements to the rest of its tiles - a couple of grasslands, the mountain, and the hill. In particular, we might want to work that mountain later for the gold, so a road and mine wouldn't be a bad thing. We have plenty of food production here.
* Tonawanda still needs tiles irrigated.
* Hlobane needs to be thrown a bone for an expansion first. Then it will need irrigation everywhere we can get it.
* Kagoshima has many tiles that need improvements to its south and southwest.
* Mauch Chunk has some jungle tiles still in its radius that need to be cleared. Also, it looks like the hill north of the city is still unimproved.
* St. Regis would benefit from a harbor, a little extra irrigation west of the city, and some mines in its mountains (the irrigated floodplain helps the food issue).
* Centralia has one hill that should be improved soon for its seventh citizen. It's NW-N of the city and there are some workers standing on it.
* Akwesasne is kind of an unfortunate mess. To keep food production up, we'll almost certainly have to irrigate grasslands after we finish the forest chop and rely on hills and mountains for production. This might not be all bad, though if we do it, it's a long-term project that will definitely take some serious worker-turns.
* Caughnawaga needs some extra mining, roading, and irrigation. Less corruption would help a lot here, too.
* Oka needs more irrigation.
* Nara needs worker-turns everywhere. And a friend.
* Camp Mistic still needs its jungle tiles cleared. One of them is gone and there're workers hacking down the others.
* Panama has one jungle tile that needs clearing.
* Zimbabwe still needs serious worker-turns in all its tiles.
* Kyoto needs a border expansion in the worst way, but it also has a couple of grasslands that could be worked on.
In summary: A lot of our desert cities still need irrigation work to be productive. Cities which have a lot of mountains or hills in their radii are in the interesting position of needing more food and having none; a lot of them have mined grasslands. Now that the Despotism penalty is gone, I think we should consider mining the hills and irrigating over the grasslands, which would allow our city size to grow and produce a comparable number of shields (then we will be working more tiles for more commerce). Cities in old Zululand, old Japan, and outside the first ring need the most work. Some cities will be helped a lot by a harbor (food production, anyone?) and a border expansion.