I'm putting the finishing touches on plans for a PA to CA loop roadtrip for mid-April to May. Here's the rough route:

Philadelphia -> St. Louis -> Colorado Springs -> Santa Fe -> Grand Canyon -> Las Vegas -> ???? -> San Francisco -> Yellowstone -> Mt. Rushmore/Badlands -> Chicago -> HOME

All that in 20 days. First: am I nuts?

Now, about those question marks: I'd like the Las Vegas to San Francisco segment to include driving through Death Valley, seeing the big trees in Sequoia NP, and visiting Hearst Castle in San Simeon. I have about 2.5 days to spare. Can this be done at a non-breakneck pace?

This section is giving me some headache trying to plan a route. There aren't any direct interstate routes and I have no idea what kind of time/speed to expect on smaller roads (like CA J41).

Any tips would be appreciated. Thanks.