We did nearly the same trip, you can see some points of interest on our blog Route Map
Also, are you a Passport America
member? It's saved us quite a bit with their 50% discount and if you camp a lot I would suggest you look into it. There are some others like Escapees and stuff too, but I don't have experience with them. Good Sam gives you 10-15% off and AAA will give you 10% off. Most every park we pick honors one of those but with the 50% we of course use PA as much as we can.
We left mid morning so the snow had some time to melt in the I-5 passes since there was a huge storm for 4-5 days right before we were to leave. Go figure.
I've linked all the names of the parks below to the official site, but if you want to see more what we thought of it and some pictures, you can check out our blog
or just the rv park reviews
First night, we stopped at Rolling Hills Casin
o which was recommended to us as a free place to sleep that is clean and safe. They have an RV park also, but you can park in the truck area for free of course it's just a patch of blacktop but it was not bad at all. I've stayed in much worse truck parks, this one was about as nice as asphalt can be. There is a gas station with store, a building with showers, etc (didn't go in there, you probably have to pay) and a hotel right next door. Then there's the casino for food and entertainment if that's your thing. It's right off I-5 south of Redding and easy to find and get to, no busy roads and winding about off the highway.
We looked at probably the same place in Sacramento, but it was right in the city and seemed expensive for just an overnight.
We stayed in Bakersfield one night also, but I would recommend not staying there as Bakersfield isn't really a great town. The RV park was great, but you could go on past it and not miss much. (Sorry to any of you folks who like Bakersfield, maybe you found a part of it that I didn't see) but if you want to stay there, this place is really nice: Bakersfield RV Resort
After that we went to Ventura, CA which isn't on your route, but from there we came back through Indio, CA (next to palm springs) and stayed at Indian Wells RV Park
which was really nice and reasonably priced, again with the PA discount.
From there we drove to Yuma and back to Phoenix. Where are you staying in Tucson and when do you get there? We'll be down in about a week and I'm trying to find recommendations on places to stay there.