I use the big eye hooks too that come on the sign with two big caribeaners to hang it off the bike rack that's at the front of my pop-up. After I slide the front bunk out the sign is actually under the bed (and out of any rain).
I just put in an order for my Musket Mikey sign and would like to build a sign holder for it. Does anyone have ideas on what is the best way to build the sign holder ? (any pictures of your sign holder would be appreciated). Or does any one know where they sell them?