Unless you get a lot of rain, Tapeats probably will not go that late in the season. Havasu Creek is also one I scoped out on side hikes. My advice is bring the most comfy and kick ass glass green front surfing boat you have. Unless you want to just practice flat wheels the whole time.
Comfort is key because no matter what someone tells you, this one is about the scenery and side hikes. Sure there are fun big rapids, but the play is not the key. The huge amounts of flat water and just lounging makes it one the the best around, float, bloat, eat, camp, sleep and have a blast runs ever!
I am already jealous. Filled the permit yet?