We have a bit of shade cloth, then use the square foam clip together mats between it and the swag. Gives you a bit more comfort on rocky ground, protects the bottom of the swag and stops condensation forming on the bottom of the swag. You can get away with 6 mats if you're packing light, we usually use 8. We stash them under the swag on the roof rack when travelling.
A stretcher would be great but with our swag being queen size, the bar up the middle is a PITA, although it might keep him on his side :-P.
Cheers Kim.