>>1020953>>1020962t. clueless
Look at a map you dips. The places they are going are not "in LA". They're a National Forest and National Park for fuck sake. Some of the best locations for recreation in SoCal, pic related.
OP, tell us more information about style of travel, skill level, bikes you'll be on, etc.
These areas will be pretty quiet during your trip, and often remote with minimal services. They'll also be cold (for California, not for you), so ideally you'd have 3+ or 4 season equipment if you're camping. ANF has elevation and JT is a desert, both have night lows in the 30s.