Well, creating a PRR theme is going to be hard to do with anything other than motive power, passenger cars and cabin cars (cabooses to non-PRR fans). My suggestion would be an oval with two passing sidings on the inside of the oval. Put two passenger stations (one at each siding) and let your GG1 train run from station to station clockwise. Run your 671 Turbine and freight train counterclockwise to meet the passenger station at each siding. Add one more switch off one siding to place your freight house and let your freight train work that siding while the passenger train sits on the other siding.
Maybe make the station and freight house part of "the city," and make the other station a suburban / small town area. Could be Columbus, OH and Xenia, OH respectively. This allows you to use O42 curves to make your equipment look nicer and run easier.
Just some thoughts of mine.
Chuck
