Hey David
Late March/Early April is one of my annual trips from the Badger Pass ski area to Dewey point...an easy snowshoe where we typically spend a couple of nights hanging out enjoying the views. Unfortunately, with the extremely dry winters that we have had recently, the past few years have been backpacking trips to other parts of the park. The high country this past March/April looked like a normal July in my opinion...dry...dry...dry...trip report
here. . Pretty much anything was accessible. So a trip similar to my report might be a good option for you if it is dry.
That being said, it appears (fingers crossed) that with the big El Nino forming in the Pacific, which affects our weather, we will be having a "normal" winter, which means that most of the high country could be under 5 to 15 feet of snow. But, if it is like last year, zero to 1 foot of snow. So I guess that I am saying that it is hard to tell right now. And that time of year you might have to revise or cancel a planned trip at the last minute due to a big storm.
As mentioned by ttilley, your best bet if you really want to be in Yosemite would be to plan on skiing or snowshoeing. And if the weather gods give us another dry year, then you might be able to walk. Its just so hard to say right now.
If you are going to be in the Northern California area then, there are certainly plenty of hikes that could be done if Yosemite is not appealing (too much snow, for example) at that time. And perhaps let us know if a snow adventure would be to your liking??