Eucalyptus has 3 parking areas and multiple bathroom buildings. When we visited there was a motorhome set up in the farthest loop and they were obviously camping in it. Beyond setting up a motorhome in the parking lot (which I honestly didn't look at the signs to see if this was allowed) there is only 1 pull in campsite and it's immediately off of the first parking lot. There is a dirt road off to the left as you enter the area that you can use to get to campsites but it is for high clearance vehicles and 4 wheel drive only (just my 2 cents). Most of the area on the dirt road has powdered dirt and it was easy to get stuck. If you don't mind parking and carrying your gear in there are plenty of campsites located within a few hundred feet of the parking areas and very close to the river.