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@HMBxplore said not many public 4wd trails in the county or along the coast from HMB to Carmel. South of Carmel on highway 1 there is the Old Coast Road and South Coast Ridge Rd. further south. The closest 4wheeling area would be Hollister Hills SVRA.
Campgrounds:
Big Basin Redwoods SP
Henry Cowell Redwoods SP
Portola Redwoods SP
Butano SP
New Brighton Beach SP
Manresa Beach SP
Sunset Beach SP
KOA Watsonville
Memorial Park
These CGs are reserved and booked months out. Best bet is to show up early at the campground on the day you want to camp and check for cancellations. Your chances of getting a spot are slim for Friday-Sunday. Weekdays are decent.
Plenty of people boondock (in vehicle) along hwy 1 north of town (some of them full time lol). But I wouldn't suggest it.
Nearest dispersed camping I would say is in Los Padres NF a couple hours south past Big Sur.
Anywhere and everywhere along the coast and in the mountains are a photographers dream. Point and shoot. Seriously.