Im hoping to install a solar panel on my roof to help the batteries with the 12v fridge and Im looking to mount the panel on the stock roof rack. Does anyone know of a bracket that will attach to the cross bars?
Yakima Universal Mighty Mounts should give you some mounting options. I use them myself for different things. Also the Yakima 24H Mighty Mounts if you can still find them (they're discontinued).
The bottom portion that you need isn't difficult at all to make cut some 1" flat stock down to just under 1" and drill and tap a couple of holes for 1/4" or m6 button head bolts and your good.
Feel free to share more info on the solar panel system that your running and any results you have. I've been thinking about trying this for a while. My second battery only lasts a couple of days running the fridge if I don't run the truck, which isn't bad but still puts a lot of strain on a very old alternator bringing it back to life all the time.