We go to a lot of state park campgrounds that have hiking trails in the state park, so we just walk to the trails.
We tow our camper so after setting up at the campsite we can just drive the truck to wherever we want to go.
Depending on the "trailhead" and parking, sometimes you can park a camper there - this all depends on the size of your camper and how big the parking area. You don't want to "barely" fit, as you won't be able to get out if it fills with cars. Also, you don't want to take up too many parking spots from other people who would like to park.
When we camp in new areas, we spend some time before going researching the area, and sometimes drive through it (if we are close) to check out parking and things to do.
