Paul is absolutely correct. Hwy 120 over Tioga Pass will definately be closed. Sometimes closed to as late as July. Not withstanding, 120 is probably the best road into and out of Yosemite, then 140 from Merced followed by the narrow and chassis twisting 41 out of Fresno. We travel 140 through Mariposa from Fresno to avoid 41. 41 is fine in a car. As with most curving mountain roads, someone always wants your side of the road (I like being in the MH better than on our motorcylce when that happens).
Be sure to visit while you are out here. Groveland on 120 has a nice campground http://www.yosemitepinesrv.com/
. Maybe the best way for you to experience Yosemite will be to stay in the San Joaquin Valley and drive the toad into and out of the park. if you drive up to Groveland with your RV, you could back track out to 99 or drive into the valley and take 140 out. If you have any more questions you can e-mail or PM me.
Now for the road over Tioga Pass when it is open. From the Valley to Crane Flat, the road rise from about 4500 feet to 6500 feet. 3 tunnels and a short rock wall on the left side(going down into the valley). Crane Flat to Tioga pass 120 is a good road. Only one section of this road do I really grip the wheel. The curves in this section aren't sharp but the scenery wants to PULL your eyes from the road, and there is nothing to stop and errant RV or car placement. There is not much traction on a 45% slope of granite
From Tioga Pass to Hyw 395, The road is carved into the side of the mountain, with about 6 to 8 miles of 8% downgrade. We have been over this pass 4 times in the DP and many more in a car/pickup. Best speed for us off the top is 25 mph and 3rd gear. I stop at the top to and let cars by, but I do not pull over on the downgrades. There is plenty of passing opportunities for cars, but most won't pass. They are just as busy watching the road or not watching it
. The road has a few places it flattens out with large gravel pull-outs, and that is where I'll clear traffic, and take time to look at the view. You will be tempted to let it run near the bottom but don't pick up too much speed as the last 3/4 miles or so to Hwy 395 is downhill with a stop sign at hte bottom. I like to save my brakes. The gas station on the south side of the road just before 395 is a good place to stop. 395 is a great road and if you have time take the June Lake Loop. Great campgrounds, but not like Outdoor Resorts
We have been over many mountain passes in the west, but Tioga Pass has to be one of the best. It is a very different view of Yosemite that isn't always shown. The smooth granite, aline lakes and meadows just shouldn't be missed. Plus, when it's wall to wall people in Yosemite Valley, it's much less crowded up high.
Hope this helps anyone thinking of experiencing Tioga Pass.