I am no stranger at free roams, as I have made one for most of the routes I have. If you look at my Steam Workshop, all I have is free roams. Most of the free roams on the routes in Train Sim, I find them lacking. You are plopped down at a station with selection of trains, and then after you leave the siding it is like a ghost town. No other cars in industry sidings, no other trains, etc. Then it is basically a quick drive where you can control the switches. To me, a Free Roam means that you are able to go out and do whatever the heck you want on the route, be it switching or running an express train.
Also, I plan on making the scenario set in the early morning because my personal computer cannot handle anything other than the lowest of graphics settings, and Dynamic Lighting has to be off so night operations are horrible for me. I'll just fudge it and say the bridge is undergoing repairs or something, so they are providing daytime freight service.
Thirdly, I realize that playing the scenarios would help, but I don't have a lot of time on my hands to play.
http://steamcommunity.com/profiles/76561198189164674/myworkshopfiles/