If you're looking for the combination of boat rental + decent chance of catching some kind of bass + within two hours of DC, it's a big list. It gets complicated since a lot of the boat rental places go to weekends only after Labor Day, so check facility websites or call.
I like Occoquan Reservoir in VA, with boat rentals at Fountainhead Park (Fairfax side) or Lake Ridge (Prince William side), but picking apart a bigger lake is a challenge. Good largemouth population, catchable enough that there are frequent low stakes local tournaments.
I've never fished it, near Motts Run Reservoir that Brian posted above, there is Hunting Run Lake, which VA DFW promotes as one of the better bass lakes in the state.
Little Seneca Lake, which is in Black Hills Park near Germantown, has gin clear water and giant bass that I can't get to bite. You may want to try the smaller Clopper Lake, which confusingly is in Seneca Creek State Park in Gaithersburg to the south. I have caught largemouth there.
Belle Haven Yacht Club in Alexandria has boat rentals on the tidal Potomac and is probably the closest and easiest boat rental near DC where you can find decent access to the "classic" bass and snakehead waters of the tidal river.
There are more rental places, and if you're open to fishing from a rental kayak or SUP, that opens up yet more spots. Cheap plug to join the PRSC meeting on 9/28 which I posted elsewhere. I hope this helps.