I made an 8x10 box camera from black foamcore board and black gaffer's tape, with a base of plywood for stability and to keep the center of gravity low to minimize wind-induced vibration atop a tripod.
I made a storage slot behind the film plane, about 2" deep, with a movable partition that divides the storage space into two parts, one for exposed and one for unexposed paper.
For attaching the paper to the film plane, I used several pieces of double-sided tape. Provided it's not too sticky, it will detach from the back of RC paper fine. If not, you can use loops of painter's masking tape.
The camera is changed out/loaded using a changing bag.
I also build a 5x7 version with similar design, except I cut down 8x10 paper into 5x8 pieces and use the extra 1/2" on either side to hold the paper in place using thin sheet magnets, which are connected via a gaffers tape hinge from the sides, with a sheet of galvanized steel painted black behind the paper at either side, for the magnets to attach to. This system has proven very elegant in operation and easy to reload in the field.
One thing I've found handy for these kinds of one-shot cameras in the field is a small 3-legged camping stool to sit on while using one's lap to hold the changing bag and camera during the reloading procedure; this is especially handy in situations where there's nothing convenient to sit on.