Blossom is a great place to see a concert. Really love the outdoor aspect and huge lawn. I've seen several shows from the pavilion, and some from the lawn, and both are great. You can't see much from the lawn, and everyone stands the entire show, but it's definitely loud out there. Great for people watching, too.
The bathrooms aren't too bad, there's a few bathroom buildings, not outhouses or anything like that.
Eat and drink before you come, though. I hate that they charge $11.50-$13 for beer!! There didn't seem to be many food options either.