lurker's comment:
Perhaps rushing some units would help move this along. We have 603g at +80gpt.
Many people talk about the exponential factor that makes an early GA not (quite) as bad as some people think and that also makes the agri trait so strong.
The same exponential idea applies to gold reserves. Until you get Wall St., there is zero return on stored wealth (and even then it is capped at a 5% cash-on-cash yield on only the first 1,000 gp).
So, until you have Wall St., stored gold is wasted value. Sometimes it serves a particular strategic purpose and you want to store it. But most of the time, it is just a fallow asset.
What can you do with stored gold?
1. Feed trade
2. Rush economic improvements (mkts, libs, unis, bks, etc.)
3. Rush units
4. Deficit research (now)
5. Steal techs (or perform other spy missions)
6. Upgrade units
Numbers 1, 4, and 5 are out of play because of the AW variant, the GLib, and the current age, respectively. That leaves rushing/upgrading. Rushing economic improvements has a multiplier effect that can simulate interest on the wealth you would have stored. A similar effect can be achieved by rushing/upgrading units to take territory/slaves faster and expand the production/farm base.
So, unless you have a greater strategic plan for the cash, it is generally better economics to put it to work accelerating infrastructure or unit production/upgrade.
Of course, the other strategy for stored gold in this case is to stockpile it to fund deficit research later when the GLib goes obsolete. In normal games, I don't like this strategy because of the loss of the compounding effect. In AW games, it can be a better strategy. (1) You'll normally emerge from the GLib period behind the leader if there is one clear tech leader. (2) Being in monarchy somewhat limits the total economy relative to normal games. Combined with the fact that most other civs won't be in monarchy most of the time makes this more troublesome. (3) With the addition of the typically high AW unit support, post-GLib research can be a real problem. As you're generally wanting to race to cavs at that point, a store of cash to fuel deficit research can be nice (as the
potential research is not limited by unit/building support).
You just have to weigh the potential research funding capacity of the territory you will take sooner with rushes/upgrades against the value of being able to deficit research for a while. One other thing that makes the "save up for deficit research" strategy potentially stronger relative to the "buy an army to take territory" strategy is the difficulty of safely improving science farms in newly acquired territory. It can take a long time to turn new territory into science farms when there are always enemy units about. If a lot of the new territory will be exposed or will be hard-to-clear jungle land, you may want to save money. If it will be sheltered and have lots of grassland, you may want to buy an attack force.
Sorry, there's not an answer in there (and I've written a disorganized stream-consciousness ramble), but I think those are the key questions.
Finally, as this is a TDG game, it may be a good opportunity to explore the art of shortrushing. I've never looked at your save, so I don't know each town's shield production, but if you have many that are at or slightly above 5 or 10 you may have good short rush opportunities. The extra 40 gold that is saved can quickly add up.
If you are trimmed to the right shield levels, you can basically double the production speed of a 5-shield town by rushing an archer, then letting it finish a MW in two more turns. Prior to getting knights, five and ten (or slightly above) are the key numbers, as most of the production will be 20/30/40 shield items.
Shortrushing is critical in poprush governments (because people aren't fractional and because in small towns it can be the only way to poprush at all). It is less critical in cashrush governments (as each shield has a 4gp cost, so there is no mismatch waste in rushing something with, say, 8 shields left). Nonetheless, it is a good learning exercise and a way to avoid burning all of your reserves too fast.
In essence, every time you do a full rush (with at least one shield in the box), you are binning gold = 4 * the shield production of the town.
One of the trainers or MMM Othniel may want to talk more about shortrushing.
Sorry for the ramble, but these are the kinds of strategic/economic questions that make Civ so fascinating to me.