I saw The Replacements there last year. Hands down one of the best shows I ever went to. First of all, it is super easy to get to by train, either Long Island Railroad or the E Train gets you there very quickly.
Then you get off and start your short walk to the stadium and you feel like you are in another world. Forest Hills is a BEAUTIFUL neighborhood that is designed to look like an English Garden neighborhood. There are Tudor Homes and buildings lining the treelined street that you walk to the Stadium along. There are some bars and restaurants for before and after as well.
As for the Venue itself, it is an old old stadium that to me, has lots of character. There is a beer garden with food vendors the set out in front and you can walk in and it is pretty laid back. You can get tickets to sit down or stand with everyone else. All seats seemed good. For the Replacements, I preferred to be down rather than up. Maybe the other way around for Van Morrison?
That sound was really good and if you have a nice night, it should be a great experience.