Thanks for the feedback.
2nd: I haven't decided whats going there yet, maybe a building that you can enter, or one just for looks.
3rd: I'm going to make a wall next to the far right entrance. all it's there for is just so the red's can get to that part of the map.
4th: Yeah I don't know whats going on there, It might be my really messy brush work, since what I've been doing is making a big brush and then clipping it instead of making lots of brushes, so theres lots of unnecessary splits in the walls.
Thanks for the comments I'll get to work on it.