Any simple portable solar panel stand/bracket ideas?

The white backing of the panel is fragile for solar cells like the blue front is, so don't prop it up against the white backing.

You need to use the frame for propping. I found it necessary to put a board across the frame at the back bolted on, and then prop it so the cross-board takes the weight. Also the board makes a good tie down place if you use bungees while propped.