Logan is full of Voltorbs and Magnetons.
If you're on the T in Boston, check out the Aquarium stop on the Blue Line and Long Wharf. The Esplanade gets a lot of water spawns, too.
Gyms in the burbs are pretty stable these days, so don't resign yourself to losing coin.
I don't make it to Needham too often, but there are plenty of stops in most town centers, due to historic sites and monuments and such.