Wow! You are like right next door to Yosemite! That is a great place to go! They have places dedicated to camp with horses. Atleast they did a few years ago.
Oh! Also you've got Sequoia NP right next to you too! That would be amazing to ride trough!
Another interesting site is www.teviscup.org They run an endurance race, from Squaw Valley Tahoe to Auburn (100 miles in 24 hours), along the western states trail. On their website they have maps and photos of the entire trail that they cover. I hope that these help