What I'm going to do for my level

I've decided to stick with my first idea, which is to have the track going over farm land and the moors. The viaduct idea I'm going to stick with, but not sure if track will still go over and under it. the level is going to have to be a point to point track.  In the level i hope to include:

• At some point in the level i would like to have a viaduct, maybe a the centre between a small valley. 
• It will contain farm houses, barns and houses doted around. I could add factory but it mite not fit. still got research on subject 
• drystone walls and farm sections
• old dust roads, dirts tracks 
• small stream, river 
• hills in the background
• Railtrack 
• Small hamlet/town