The quickest way to get some basic ideas is to go look at the model railroad sites - this question is a perennial favorite and somebody is always coming up with new ways to handle the problem. 1:54 is close enough to O scale that scenery products designed for it will look fine, but 1:11 is going to require scratch work on your part. Still, it's not that hard to do, certainly easier than scratch building vehicles, buildings, etc.