Time est. for Green Ridge ORV

Next weekend, we are going camping at Rocky Gap St Pk... a family thing w/ some of wife's friends.
Right now we don't have na yspecific activities planned so I figured I might go check out the ROV trial at Green Ridge, since it's practically next door.
I've read lots of reports that it's not really challenging, but a nice scenic drive, which is great b/c wife isn't really into wheeling but she DOEs like riding in teh back of the Runner topless (the truck, not her, sorry ), so I'm hoping maybe this can be a nice segue...

Anyhow... from the time entering the Green Ridge gate (I'd be coming down form 68) to leaving, roughly how much time should be aloted? Just a few hours, or several? looks like Mertens Ave is only ~15 mi from our campsite, so would it be feasible to just go after lunch, be back by dinner?

Any thoughts?

I believe it is just a 12 mile loop with little if any actual terrain on the trail. Just a dirt path on the mountain with a view on one part. Yes I believe you can go at lunch and be back for dinner.