Sacramento is anything but flat to the east. Hopefully your son can find a place a little east of town. I used to live here:
https://en.wikipedia.org/wiki/Folsom,_California
It's basically at the foot of the Sierras, and endless climbing in all directions. Plus a river trail bike path that will take you downtown, I believe. It's a true cyclist's paradise if you get yourself situated in the right area. From Folsom, keep going east and you wind up at Lake Tahoe.
