I can't answer for all the parks, but I had an awesome burger and fries at Liberty Tree Tavern for lunch on Saturday! It's not a counter service place, but the burger was thick and juicy (looked like it was hand pressed, but probably not) and awesome! I got it with cheddar and bacon, but you could also get swiss or provalone (I can't remember which) and mushrooms if you chose. The fries were fries, but the burger was great!!!!
~Beth