We stayed at Hickory Hollow for a few nights a couple of years ago. We recall a nice place, well kept, nice folks. No problems with anything, and we'll surely go back next time through the area.
We've stayed at all three commercial campgrounds in that immediate area-- HH, KOA, and Cozy Corners. All three are good, but HH is certainly the best of them. Cozy Corners is the most homey, a mom n pop place, but iirc, has only water and electric, and the ground can be a bit soft if you stay after a rain. I have heard very positive reports about Starved Rock SP, but never could book far enough in advance to get a reservation there.
John & Diane, fulltiming since '12
'02 DS, FL, Cat, '04 Element
John & Diane, Fulltimers. RVM103 NHSO
On the road since June '12 with Lincoln, the guard cat.
2002 Dutch Star 40, Freightliner, Cat 3126, 2004 Element