I would reserve a spot ahead of time, avoiding any site in loop 'E'. That loop is for those planning to camp with horses. There are hitching posts at every site, therefore, lots of horse poo. And not the best place to take a dog because of all the horses in the area.
The camp host at loop 'E' and 'D' is very nice, and is willing to split up group areas to individuals who have no where else to set up camp. If you do this, expect to get to know new people as you will share a fire pit and eating area.
The fee to camp for one night is $20, but that includes access to any of the Payson lakes, which is $8 for day use.
We didn't go on any hikes during our stay, as we bummed at the beautiful lakes (only the middle of the three lakes is dog friendly) all day. However, there is plenty of hiking in the area.
Very hot. Around 90 degrees. Wake up and get breakfast early. Then enjoy the water in the heat!
P.S. 3 stars due to the fact that I had to camp in horse crap.