I just cleared Stuyvesant and have been doing everything solo, clearing every neighborhood of its side missions and main missions before moving on to the neighborhood with the next highest level range.
So far, I've been able to accomplish this with minimal hassle, since completing every mission before moving on to the next area leaves you comfortably over-leveled.
My question is, at what point is this not the case? I'm guessing that, as I move north through the eastern neighborhoods, I'll eventually hit a point where tackling everything solo becomes significantly harder despite my current level. Can someone provide insight on this? I'd like to know if I'm going to hit a wall before I actually do.