Here's my thoughts Paul. I like the V3 because we could have operating sessions in WIndsor, Kentville, Middleton, Digby, Yarmouth all at the same time without any congestion in one area. If there's only 2 or 3 players at first, we can choose which area we would all be in. The dispatcher could zoom down to a session and take a look - I'm think capturing video for use later on (maybe museum or as a record of session for YouTube). We can stream it live too.
I like Open Rails because we can set up a folder structure just for the DAR and keep everyone on the same page with activities and rolling stock. Your other MSTS folder with all your other routes can stay the same with no interference. It would take a bit of work to make sure this is all in place but I'm betting there's at least 5 of us that would like to do this - maybe on a continual basis like once or twice a month for a few hours at a time (1-1/2 to 2 hours).
An operating session like a club is more what I had in mind with a dispatcher who controls train movements and has the master schedule.
http://openrails.org/share/multiplayer/
Each player in turn accepts an order to run a particular train (Extra 8136 for example) and proceeds on their way to assemble and drop off as the order demands, reporting back as they pass stations along the way so the dispatcher "knows" where they are. Then we will have regularly scheduled passenger service and gypsum train service too a; depending on how many players join in.
Really, no automation, just running it like I said, like a club would. The only thing we do is create an activity that sets out all the rolling stock. Then players are assigned their order, jump in their locomotives and go with the dispatcher overseeing and maybe even playing if the player count is only 2 or 3.
As for the activities you mentioned, it looks like Open Rails is headed in a different direction and there are new tools to do that in Open Rails. Have you tried the Timetable Editor yet?
That's sort of my brain dump on the idea. Nothing in stone, just what I had in mind when I wrote the post in the first place.