I agree. Even without seeing the picture I can tell two things, one is that you have a lot of space to work with so whatever is decided upon will work out great, and two, you have no vision of your layout. Any layout, from 1x4 to 200x200 needs a concept of design and operation, in other words, a reason to exist.
Urban or country will work either way, but only with a clear concept of what the railroad is trying to be. Urban works well with huge freight yards and intermodal facilities, passenger trains everywhere, and verticle scenery in the form of buildings. Country can be long trains, small town industries, desert or mountains, wood, coal, etc.
Only you can decide. I know what I would build, but you might not like it, maybe find it boring or plain. Read those primers, go to the public library and check out some books on model and real railroads.