I don't know if they will let you just "Drive Around" since the only parking is on the individual sites and that is reserved for those guests staying there. There is the Lot out front, but that leaves you "Walking" around the Fort. You can use the "Bus" transportation to get to the TE or other points of interest but it's not really that great for checking out the Campground.
You could try and rent a Golf Cart for your visit too, but it's a lot of money for just a couple hours of touring.
As far as "Highlights" go, there is the obvious things, Settlement, Outpost, Marina, Pools and Meadows Area. Depending on the time of year (and holidays) many campers will also decorate their sites and campers. Some will do it regardless of the season or holidays. So it's really tough to give a good "Touring Plan" based on that.
Now I am sure Ed will be in here soon enough and point out some hidden gems. (He's great at that) that could be of interest including some remnants of the old railroad.
Sadly, some things may be more difficult to access now too as a result of recent incidents, but of course we want you to be safe.
Hope you enjoy your trip.