A lot of people round Rancho/Fontana ride up cherry (changes name when it turns), up to Donkey road, at the end of donkey road is a gas station where you can rest, then tackle either Lytle creek up sierra avenue/lytle creek, or can go up to the San Manuel ampitheater. Mostly less traveled roads here although most don't have bike lanes. An up and back route will get you about 30 miles.

Or you can ride to Glendora on Foothill and turn up towards GMR, where you will see lots of forum members riding and then ride back from top of GMR (GMR is a little higher difficulty but worth the ride, 6% average)

can ride to redlands area and ride upper SART too