I started getting ringing after a few nights out in a row, so looked into which earplugs to get and came across these:
https://www.acscustom.com/uk/products/pro-series/pro-17/
Now they're pricey, but £149 to save your hearing feels worth it to me. Its equivalent to one or 2 nights out in terms of cost. You go to Boots or similar, get impressions of your ear canals done and then custom earplugs sent to you a few weeks later. Now clearly they're not as good as listening to music without protection, but they are leagues ahead of any other earplug I've ever used. Secret is to use them for half hour before you go to a gig/club/start playing drums/Djing etc as you become acclimatised to them and then the difference isn't nearly as noticeable.
Cannot recommend them highly enough
Can't answer you on the camping as we're always staying in Leuven at a hotel (paid $315/night this year at Park Inn), but getting back and forth is quite easy, if you don't mind the 15 min walk to/from the bus stop (it's a nice way to get sober). There are shuttles going constantly and it's basically only after the main headliner we've encountered any issues with long lines. Getting up is normally no problem no matter when.
Already got tickets for their Glasgow gig, hope they do get to play Glasto again. Enjoyed their performance on the other stage. Nice bit of Americana on a sunny afternoon.