1. Can I apply the real world mod?
2. How far into the season can I go?
3. If I decide to purchase...can I keep going with the initial demo season?

TXS

I haven't used a demo in a few years so someone may come along and correct me, but

1. Yes!
2. You can play one in-game season or 1 real-life week, whichever comes first
3. Yes! When you purchase, you'll just need to enter the access code you receive. The demo is essentially the full game already just with that lock. Everything done before carries over.