1. During Alpha testing, it was found that a lot of object holes and other visual anomolies became visible when the camera position got too far left or right, so I limited the travel. The limit is always there, but when you stretch the window into a tall, skinny shape, since the camera can only look straight ahead you don't see as far to the edge from that camera position. If you stretch the window wider, the camera can see farther because of "peripheral vision".
2. Same issue.
3. I may have to put some gravel lumps over there.
4. If the area of gravel past the shell showed, you'd complain that it was too straight.
