I work with primary aged kiddies & we recently had a trip to lunar park, I opted out because I've got SPD, I know I couldn't be on my feet all day, but then I'd have been dealing with 50 + kids.
If you go maybe just take a seat when you can, take some lunch & maybe have an hr lunchbreak somewhere, walk slowly & try your best not to overdo it. Have you got a support belt? And really comfy shoes?
Or could the boys go on their own?
Only you know what you can and can't manage hun