I would say, it should be the Windsor Lines which are the Kingston Loop, Hounslow Loop, London Waterloo to Weybridge via Staines services, London Waterloo to Windsor & Eton Riverside, London Waterloo to Reading, Ascot to Aldershot. I think it should be be set in the early 2000s, with 4VEP, 4VOP, 4JOP, 4DES, 455. The reason why it should come with these units is to give a greater pilferer of rolling stock and services. Also you could have it so that you can go in Feltham Power Signal Box and Wokingham Signal Box to give a greater interest to the route, if possible it would be nice if you could move the levels so that you can control train moves. Also this route could have a GWE layer between Reading and Wokingham for the North Downs Line services. Also by being set in the early 2000s you would have another version of Reading to look at with all electric trains at this time worked in and out of Platforms 4a & 4b.