Aww, heck, Popeye's ride is one of the few rides at IOA that non thrill ride people can enjoy.
September is always a definite week we do USO/IOA (we own a timeshare around a corner and Sept.'s our week). Popeye can absolutely be done with no rash and no chaffing on the thigh. It can be done over and over and over
Wear cotton clothes, light shorts and shirt -- no denim. Don't wear socks and sneakers. Have rubbery flip flops or
crocs or something. Socks and sneakers in September heat with afternoon thunderstorms is a bad idea, IMO, anyway. Bring a poncho you paid $0.50 for at your local Dollar Store back home. Save Popeye for last, put on your poncho right before you get on the ride, and make sure your butt, front and back, is protected with the poncho. September is so dead with crowds, more than likely, the TM will let you just stay on the ride when you're done, so you won't have to keep re-adjusting the poncho.
You will get off Popeye 80-90 percent dry. With heat indeces in the 110-120 range -- remember, Orlando isn't coastal and doesn't get the seabreezes other parts of FL do -- a splash or two on your neck and legs will be wonderful.
My mom and I can't do thrill rides, and there's no way we'd ever give up Popeye. It's the one ride we can do 20 times in a row! With a poncho and the right shoes, it's not a problem at all. Your feet, shins and neck are dried by the time you walk to Marvel Island or JP.
Oh ... donate the poncho when you're finally done! They sell them at the park for like eight bucks. We just returned from a trip to O-Town, and every time we were done with our ponchos, a family asked for them. Worked out great.