Hi again Wolf

,
Generally you're going to need more cities - and this will be best done by going after Mansa again. I'd do as it seems you are doing, and pursue Chemistry and start churning out Grenadiers. Optics will be a handy pick up though as your next tech'.
Your cities are poor

producers, and this is a concern. The landscape hasn't been kind to you in that regard, in that you've been put in generally flat land. Walata is your best production city in waiting, and this is where I'd start looking at your unit pump.
There's a problem with food counting and over-Cottaging - Boston being the main offender where your city stagnates as soon as you work the Gold Mine (and if at all possible, you should work your Gold Mines!).
Civics:
I would undertake a big revolution;
- Legal: Swap from Vassalage to either Bureaucracy or Free Speech
- Labour: Swap from Serfdom to Slavery
- Economy: Swap from Decentralisation to Free Market
Terrain Development:
You have two Workers in the noth east doing 'Lord knows what' ... one's building a road in Tundra, another's just built a Workshop on a tile outside of any workable fat-X, one seems to be sleeping in Washington (?). These guys surely can be doing something more useful - Walata needs lots of development.
There's a Settler in Washington - not a lot of great potential city sites in your empire at the moment, but I'd go for the Clam-Clam-Flood Plains in the south and use it as a lightweight

-yielding Fishing Village.
Two Work Boats would be helpful for the second Clams and the Fish - the former for a new city, the latter for

.
Cities:
Philadelphia: It's not putting you over the happiness cap, but this city has no military presence and giving you two unhappy faces. It can't feed the citizens working the Workshops until you move into State Property. Farm the north-noth-east Grasslands and replace Grasslands Workshops with Farms for now. I'd suggest a Work Boat (refer below) and going after Optics and then getting out some Caravels.
Walata: One of your new cities, and looking like a good production point despite the two commercially-oriented special resources. Farms and Mines here.
Awdaghost: Mansa didn't do you any favours with the placement of this city in that it's missing the Gold tile. In light of poor

production in your empire, focus on Farms and Mines.
Washington: Will be reinvigorated
if you opt for Bureaucracy - I'd prioritise Forge and University over Grocer. If you get your Work Boat to work the Fish you'll be getting

from it and thereby address the

.
New York: A good commerce city. I'd opt for a Forge, and micro by moving the citizen off the Sheep Pasture and on to the Fur Camp for now.
Boston: As noted above, food problems. Farm the Grasslands so you can work the Gold Mine and still allow the city to grow. I'd recommend popping out two Work Boats from here (
or one from here, one from Philadelphia).
Where to?
To me the plan would be to get Chemistry and re-attack Mali, which I'd imagine is where your thinking is too. I'd go after Optics next however, and start exploring the map; meet some other nations to begin trading technology, and post-Astronomy some resources. You're going to need more

, and the two Malinese cities would be where you can start to get this productivity. Six or seven cities (most with poor

yield) isn't a confident place to be for a Spaceship win ... do-able, but far from ideal.
[Edit] Played the game for a bit; Boston's soon to pop a Great Merchant, and you could consider sending him on an intercontinental and use the

for Mace > Grenadier upgrades. [/Edit]
All the best.