I think the trains have been a lot better recently. Yesterday I left on final whistle and was back at my car near London Rd station at 5.20. On Tuesday I parked right outside the Cardiff ground in their away car park and finally got out of the ground at 10.10pm which was about 30 min after game...
I wouldn't imagine the club would not be arrogant enough to announce any prices for the prem until we got there. You should expect a rise in prices though if other promoted clubs are anything to go by. You can watch on sky and dodgy streams but it nothing like being there in person!