Seminole Canyon SP
While this park has spectacular views of the canyon from the rim, the public is not permitted to enter the canyon without a guide. There are too many 4000 year cave paintings and other relics.
We spent part of the day reading and waiting for it to get warmer, then joined a ranger-led tour to the Fate Bell Shelter down in the canyon. The entire walk was about 2 miles and the cave drawings were very well preserved.
Before our walk we spent some time in the museum in the visitors center which we found to be interesting and informative. Probably one of the best we have seen, it covered the early life of the native Americans, the settlement by Europeans, the entry of the railroad, and finished with the introduction of sheep farming. Well worth 3/4 of an hour of our time.