Jim:
This is my old stomping ground - born and raised in Hemet. Hwy 79 is pretty crowded with a lot of lights in the Temecula area near the I-15 offramp. The road is O.K. 2 lane up to Hwy 74 (Florida Ave.) West of Hemet. You have to figure out your transition (couple of ways to go) to get to the North end of the Valley and to the Lambs Canyon grade on Hwy 79 on into Beaumont. The Marines from Camp Pendelton going to 29 Palms use this a route lot, you will save about 20 miles over I-215/US 60, but if I was from out of area I would go that way just to leave the cruise control on and avoid the Temecula and Hemet area traffic (although I have been in traffic backups on I-215 near March AFB). The I-215/US 60 way is all freeway, and the beginning grade up Lambs canyon is fairly steep. There is a grade on US 60 between Moreno Valley and Beaumont, but not as bad.