You won't be dissapointed !
It's a fantastic area to explore.
Hello and welcome to R.T.A.
Yosemite valley will be accessible but you will not be able to cross the Sierra's on the 120 [Tioga pass] at this time of year as it will still be closed due to snow, so that would be a big detour to get to Mammoth lakes.
Your trip is otherwise doable and a very popular area to explore. Death valley is worth a visit on the way to Vegas,it's a fascinating landscape that you won't get to see our side of the pond.
You will need to pack layered clothing as the temps can vary quite a bit during night and day and at different locations.
Have a good search of the forums and planning pages and when you have more questions ask away !