Adding to Mark's post regarding UKTrainsim, the lads there put out some incredible community freeware packs and run contests for route building and scenario creation and the results of those endeavours are available to the community. You shouldn't run out of things to do quickly
Couldn't agree more with that post. The packs created are fantastic and a lot of people have donated there items to be included, Also have tested pretty much them all and got some scenarios included with the WCML N Scenario pack as well.
As Mark said some freeware routes will require DLC to run correctly, Most common being Ilse of Wight route (brillant by its self), followed by WCML N.
Also rail-sim.de has some fantastic stuff on it as well, including the brillant Altenburg-Wildau 2.0http://rail-sim.de/railsimnew/index.php/...-2-0-for-ts2012
Which also has a payware verison called Koeblitzer Mountain Route, which will be getting a update at somepoint as well for more rail miles.http://en.shop.aerosoft.com/eshop.php?ac...anguage=english