Most people don't think Arkansas and 'island escapes', but that's exactly what Buck Island is – a Mississippi river retreat of almost 1000 acres of hardwood forest, 500 acres of beach and sandbars, and some 5 miles of peaceful trails. How do you get here? Boat: it's about a half mile (30 minutes if paddling) from Helena's main boat launch.
Quapaw Canoe Co, on the other side of the river in Clarksdale, MS (about a 30-mile drive), leads excursions out to the island. Check its website or email them (email@example.com) to see when its trip schedule is - rates are variable, and depend on how many people are in your party, if you're bringing your own lunch, etc. Quapaw may also be able to help with boat rentals in Helena.