Likewise, but i am about 99% confident that it will be compatible with existing models - not so sure about routes but then it shouldn't be that hard for them to provide a migration utility so that you just have to convert a version 1 route over. Activities, not sure about those at all, i'm hoping they do a lot of work on activities for v2 - as long as the stock and routes work, and the activity editor/capabilities are better, i think we'll be able to live with doing activities again.
Eg. I love the way that Trainz does activities/scenarios - but they're so wildly different to Train Sim it'd be next to impossible to write a converter if MSTS went the same way. On that topic, as soon as SP3 is released i'll post a screenshot story board for the activity i'm working on at the moment in Trainz
Matt.