I would not suggest flip flops. I have been to WDW many times and never had problems, but last time... We hauled our way through three parks our first day (EE at MGM, lunch in Epcot, Wishes in MK) and I honestly could not walk the second day. I didn't have any blisters, but my calves were unbearably tight. My family begged me to get a wheelchair (seriously), but I refused as I thought that would be ridiculous. I found walking backwards helped a lot (like that didn't look ridiculous!). If they strapped on or had a backing, I would have had no problem...