Hi Deb,
You would do well to reserve a hard-walled cabin in Curry Village a year in advance - they do go quickly. I've camped at Yosemite (the campground I stayed in was washed away in Jan '97), I've stayed at Housekeeping, and I've stayed at Curry Village in a hard-walled cabin with no bathroom and in a tent cabin. Lately, when we go we stay in full cabins - kitchen, living room, etc. - that are located just inside the south entrance to the park at Wawona. That is because sometimes we don't plan until March & by that time the valley floor is pretty booked for the summer except for the tent cabins.
Excursions I highly recommend:
Glacier Point - stands 3,000 feet above the valley floor. The views are spectacular.
Mariposa Grove - although you will be going to Kings Canyon and Sequoia, I still recommend going to the Mariposa Grove - take the tram to the end of the grove & walk back - it's a very nice walk among the big trees.
Valley floor - there are a lot of things to see there, and I recommend taking the free tram to Yosemite Village & check out the Visitor's Center, go to the base of Yosemite Falls. If you feel like walking, you can "hike/walk" from Yosemite Falls, stop at Yosemite Village, and continue to the Awahnee Hotel -- it's a walk along the valley floor with small ups & downs. You can also go to the base of Bridalveil Falls. The glacial moraine is here if you know what to look for -- After the glaciers carved out Yosemite, they pushed to the area about where Bridalveil Falls is, leaving a dam of sorts called a moraine. As the glaciers melted, a lake was formed, and then filled with silt, forming the floor of Yosemite Valley -- when you look down on the valley you can imagine the lake thousands of years ago. You can also go to Happy Isles & hike about a 1/4 mile up a steep trail to a bridge where you will be able to see Vernal Falls & the power of water coming down. Or, you can go down by the river (it's pretty wide as mountain rivers go), and swim. The river by Stoneman Bridge is nice.
When you stay in Kings Canyon, you'll probably be staying at Grants Grove. I highly recommend that on one of the days you are there, drive to Sequoia (same mountain range & right next to Grant's Grove). In an hour you will be at Giant Forest, where you can see the General Sherman - the largest living thing on Earth - visit Crescent Meadow, and climb the stairs to the top of Moro Rock. You will also be able to drive under the tunnel tree (a tree that fell and is so large that they cut a tunnel through it where cars can drive through), and see the auto tree. At one time you could drive on the tree, but time has taken its toll, and they've blocked it now so you cannot drive on there. You can also visit Grants Grove & walk among those giants. You can also take a drive (maybe 15 minutes?) from Grants Grove to Hume Lake & relax on the beach, or go kayaking/canoeing there. There is also a gas station there, so you can take care of business and also have some fun.
I have two photo trip reports of Yosemite & Sequoia that you might want to take a look at. The links are in my signature.
This year we are going back (yeaaa). We'll be spending 6 nights camping in Sequoia and 3 nights in a cabin in Yosemite. I can hardly wait.
I recommend going to
www.yosemitefun.com. He has put together a wonderful & informative website on Yosemite.