A couple of suggestions...
From GC to the Orange County area, there are a couple of options --
The usual places you can stay are
Needles
Lake Havasu City
29 Palms
Blythe or ...
Palm Springs/ Indio area
Needles and Blythe don't have anything amazing to recommend them -- other than a selection of hotels. I've stayed in both -- no problems or issues, other than they were places to stay because we were passing through or doing other things in the area that day.
Lake Havasu City has the London Bridge (moved from its original location). That hasn't been a draw for me, but there are selection of hotels there, and its right on the Colorado River.
29 Palms sets you up to pass through Joshua Tree National Park on your way out. On the road there from the north, you can go over part of old Route 66 (now called the National Trails Highway in that area), and visit Amboy Crater, and a few other areas. There are several small towns in this area, and there's a major Marine Corp training base there, so there are a reasonable selection of hotels.
Palm Springs/ Indio area is the largest set of towns in the area, with lots of hotels. That's probably the furthermost of your options, but the most hotels and things to see (in the area).
There are lots of places you might look at, or stop and visit along the way
- Indian Italagios along the Colorado north of Blythe
- Old Indian ceremonial spot (a labryinth) near Needles (but unmarked -- you have to know where to look)
- Lots of desert scenery along the way, including old mining towns and ghost towns/ vanished town sites if you know where to look
- Gen George Patton musuem at Chiraco Summit
- Amboy Crater
- Joshua Tree National Park (several interesting places there...)
- Palms Spring Tramway (but a multi-hour stop, minimum)
- Several real desert oases -- the one near Thousand Palms is one of the better.
- Big wind farms in Cabazon area/ Whitewater Pass west of Palm Springs
etc