There are so many sites that are great it's impossible to pick one or two. A popup can go on any site. If you have small kids, I'd recommend requesting a specific loop when you make your reservation (not guarenteed but they try). If you want to be down by Pioneer Hall, the pony rides, the play ground, beach, boat dock and bus drop, ask for loop 100, 200, 300, or one of those low numbers to cut down on the walking.
If you want to be near the pool, the bike barn, campfire, singalong, main trading post, ask for 800, 900, 1000, or 1400. Or 1500 is near these but has no sewer connections.
We have a popup and have requested loop 900 three times. We got it twice and got 1000 the other time.
Enjoy!
Bama ED