If you were to simplify things, and look at Yosemite to Grand canyon to Cottonwood before arriving in Palm Springs, without too longer days of driving, then I would consider the following.
20th. Leave Yosemite, head towards Fresno and look at staying nearer to Bakersfield, or a small detour and look around the Lake Isabella area. Miracle Hot Springs near Bodfish, or Kernville is a small quaint mountain town. Next day(21st) head towards Kingman and explore this route 66 town for the night. Then a ride along a stretch of route 66 on the 22nd, through Seligman and onto the Grand canyon NP, stay the night in the park or Flagstaff. 23rd, head to Cottonwood, spending a bit of time in Sedona on the way. Then continue to drive towards Palm Springs, until you are a comfortable distance away. Cottonwood to PS would be 6.5 hours plus, as you have an event to attend you will want to start out closer I presume. Getting close to (or just along) I-10 would give you a good start to PS on the 24th.