It's a pretty location and rather far off the beaten path. The rates are incredibly cheap but you have to make weekend reservations during the week because the Muncie Parks office is only open Mon-Fri 8-5pm.
If you are planning on bringing a tent, it's $12 and all you get is a grassy patch that's too uneven for the RVs to park.
Really cool plants! The tropical indoor area features lots of familiar edibles and ornamentals; it's awesome even if you're there in the winter. When you go outside you can appreciate how much work goes into maintenance and design. Really good for engaging children, but suitable for adults if they have a basic plant knowledge. Definitely worth my $6! Discaimer: I'm a plant nerd.
Visited with my dad on our cross-country road trip in early February. We stayed in Flagstaff and visited GRCA two days in a row. The first day was just sightseeing from the lookouts and enjoying the visitor center on the South Rim. On Day 2, we checked out of our hotel, then returned to the park and hiked the S. Kaibab trail for a few miles before continuing our westward progress. It was quite cold and we weren't used to the thin, high-altitude atmosphere, but the ice on the trail was minimal and the visitor traffic wasn't bad because it was the off season.
Absolutely breathtaking views and a much needed break from our marathon road trip and my first National Park experience outside of my home state of PA. The silence is intense and the scenery is beautiful. We went in early February and the temperature was comfortably cool. Facilities were well-distriubuted and there were plenty of pulloffs-not too many crowds.
Awesome site, but the washboard road sure rattled us around on the way there. Costs $6 a night per site (14 day limit) and has pit toilets and the water is trucked in, so they recommend bringing your own. Each site has a parking space, a picnic table, and a shade pavilion.
Like all CA State Parks, there is an $8 reservation fee unless you get there on a "walk-up" day, where it's first come first served. For all Mount Diablo sites, the price is about $30/night or $210/week.