Late Fall - Early Spring
The park closes before dark to prevent theft of its Petrified Wood
This is just a park to pass through. The park road will take you through both the painted desert and several areas of petrified forest. There are several short hiking trails along the way and you will see things like petroglyphs, old cars, and other remnants from Route 66's hay-days. You cannot spend the night inside of park boundaries. Too much of the petrified wood has been stolen over the years, and that is the main reason why it became a park in the first place. Prior to being declared a park people would fill train cars with petrified wood as well as their pockets.
It's definitely a cool place to see. The painted desert is beautiful and the quantity of petrified wood here is astounding so don't drive on by, take the short detour through the park on your way between Flagstaff and Albuqurque. I kind of wish they would do things like this (picture above) with their piles of petrified wood. Had that been the case, it's pinky up rating would have sky-rocketed adn I would have spent more time here.