We always stay in Williams at the Grand Canyon Railway RV resort. Lots of things to do around Williams.
Day trip on Train from Williams to GC. Train depot is next to RV park.
Drive to GC, a bit under an hour. Tour the rim, have lunch at El Tovar
Visit Bearizona, a drive thru animal park with walk thru area too.
Near Williams is a Deer petting zoo, several other animals too.
Have fun on the zip line in Williams. Short but fun.
Williams itself is a small route 66 town. Very fun.
Drive to Flagstaff and tour Lowell Observatory.
Williams and Grand Canyon are high altitude. Summer day temps are usually in the 70's, nights in 40's, perfect for campfires. Late June and early July can be warmer upper 80's during the day.