It's not close to NW Arkansas, but I would visit Stout's Point in Petit Jean State Park, near Morrilton, for an awesome view of the Arkansas River and surrounding area. There's even a cache there by the same name (GCTY8T) - one of mine! There are many other caches hidden in the park as well.
Another spot is Mt. Nebo State Park, near Dardanelle, which has great view points where one can see the river as well as Lake Dardanelle. There is also great caching there.
"Wildness is a necessity." -- John Muir
"When you go to hide a geocache, think of the reason you are bringing people to that spot. If the only reason is for the geocache, then find a better spot." – briansnat