How much do you want to do? Sometimes we drive up to Red Box/ Mount Wilson road and park there. It's 14 miles from the bottom and avoids the lower (scary) section. If you'd like a hilly 60 mile ride, go from Red Box to Dawson Saddle and back, (about 7000 feet of climbing). The only place to get water is Newcome Ranch, about 12 miles into it. You will need a parking pass or you may get a $5 fix-it ticket.
You can start from the bottom and go as far as you like, you could make a left on Angeles Forest Hwy and go to Hidden Springs Cafe, then go a couple miles further to Upper Big Tujunga and back to Angeles Crest and down. Questions?