Sounds like a plan to me!! never made the trip on 66 from west to east (have east to west).

I have just a couple refinements that you might want to consider. Like you I believe it will be much cheaper to stay in Santa Monica than in L.A. and not being familiar with LA you could find yourself in unsafe areas. It is not that long of a drive to see the things you want in LA from Santa Monica.

When going from Santa Monica to Vegas, if you choose to use 66, which I recommend, be sure to take it from Needles/Topock to Kingman---probably the most scenic part of the route. It is only about a two hour drive from Kingman to downtown Vegas. Add a couple hours if you stop at Hoover Dam. When going from Vegas to the Grand Canyon, go back to Kingman and hit 66 thru Peach Springs going on to Seligman for a brief stop. Unless you have reservations for rooms at the Grand Canyon, you will probably want to stay in Flagstaff. On the east side of town there are old motels that fit the 66 motief but are clean and comfortable and cheap.

So far as guide books on route 66, the best I have seen is "EZ66 Guide for Travelers" by Jerry McClanahan.

Hope I have been of some help and
Remember the journey is as important as the destination
Scotishbob