Is it possible to make a city map with all mesh buildings?

I am thinking about making a medium sized low poly - mid poly map with post apocalypse theme. I find it easier to just model the whole building rather than just building it in roblox studio. Will it be possible to just do that? I am worry about collisions and stuff because I want the player to be able to go inside the building as well.

Meshes can be double sided (so they have a back view), but I think they won’t be very nice from inside (e.g. you’ll see the same surface as from outside).
I’m sure that collision can be set properly (using precise fidelity), but I don’t have experience about how to leave a door where you can go in, someone may can explain it.