We camped at Salamander Flats which only cost $6 for a 3 night pass. There was an outhouse but no running water. The leaves were turning color and it's gorgeous this time of the year however this weekend is the last weekend to camp before the park closes their campsites for the year. If you haven't hiked, biked, climbed, fished, four wheeled, horse backed, snow shoed, or cross country skied AF canyon you're missing out. Definitely check out the AF canyon caves which requires a short semi steep (I think 1 mile up) paved hike to the entrance. It's a neat place to explore.
A few links to American Fork Canyon Activities that might be helpful:
American Fork Canyon