If it's worth doing, it's worth overdoing. How about an old U-haul trailer, mount the paper on the front end and the lens sticking out the back end. Have a tray of chemicals lying on the floor of the trailer. When the exposure's up, just flick a lever from the outside to tip the paper into the chems, drive down the road for a few minutes to provide the agitations, and you're done.
48' shipping container with a camera obscura on one side and roll-on emulsion on the other, same fixing method, slap it on the back of a Norfolk Southern container trailer to agitate it, and you're done.