I'm sure more can be said and learned about the joys of Open Rails, hopefully IN the ORTS forum and not here in the MSTS forum. Older content like that runs without problems, looks as it was meant to look, in MSTS.
Personally, I've never found ORTS to be as much fun as MSTS because of the additional workload involved to get things working right, and that's mainly because I like to run classic MSTS content like Sea View Island (for the kids), Railfan Marcel's routes (Lake Central), Isle of Ashes, etc. That's not explained very clearly when Open Rails recommendations appear here in the MSTS forum, and that's unfortunate. And some content just doesn't work the same in ORTS as it does in MSTS. you'll be spending lots of time editing configuration files instead of running trains. Open Rails is impressive, but it still is not, and undoubtedly never will be, able to run all the routes, locos, and rolling stock that MSTS can - not without lots of tweaking, i.e. You must find the disks for sale from third parties because, unfortunately, it is out of print. MSTS isn't going to be available as a direct download.