Hoover Dam is a fine visit, but only better when you park the bike and go walk on top of the bypass bridge that looks down on the Hoover
Also, the west side of Vegas is Red Rock Canyon. A cool little 13mi loop that you'll enjoy.
Just north of Palm Springs is Joshua Tree NP, and if you're hitting it on a weekday, it's a nice ride with some vista's that are incredible. There are a few different angle's into that place so no backtracking necessary.
I'm following you two on Ride Reports. Good stuff
. Oh, please break the speed limit in CA, WE NEED the $$$