Bring both

The 2nd week of June usually brings highs in the 90's with lows in the 70's, but rain storms and cool fronts do happen. A lightweight 40 degree sleeping bag will be too warm most nights, but makes a comfy pad on top of your air mattress. You can always crawl inside the bag if it gets too cool. But most nights I only need a silk rectangular sleeping bag liner. It's nice to have both options. In 2006 I nearly froze to death in Warner, so shopped for a blanket at Walmart in Tahlequah the next night. Other Freewheelers got there first and the only thing I could find was a Sponge Bob Square Pants baby blanket. Still got it, and it kept me warm when I needed it.

Light bag plus and old sheet if it gets cool, inside bag,really cold, I dress in my tights and several layers of shirts and my rain jacket.