LOTS of pop warner experience from my years visiting WDW, UO and Sea World (it was at SW last year.) Couple of tips:
1. Watch park hours. In the past, they will usually dedicate a special party or night just for attendees. This may (or may not) affect park closing times for public guests. Keep an eye on park hours in the next week or two.
2. Avoid the hotels if possible. Most of the kids are fine and Pop Warner has very strict rules and lots of adult chaperones (unlike some of the South American tour groups I've seen where the "chaperones" are basically teens who are as rowdy as the kids and fail to supervise them.)
But it's still going to be louder, busier, etc at these hotels. Google Pop Warner event hotels and view or download the event registration packet with all official hotel options listed.
Last year, they included offsite brands like Marriott, Hyatt and Choice as well, but Sea World doesn't have the onsite options UO does, so not sure if they'll do that this year.
3. Park crowds? Others may disagree, but I've never experienced much impact from Pop Warner groups INSIDE the theme parks - they're very busy with competitions most of the week and usually limit their theme park time for the special nights/events planned by Pop Warner leadership.
(Some families may come in early or stay longer, but again, not enough impact to really make a big difference in UO's large parks.)