I seen a guy on Youtube who had a Grandby with his own diy shower. He had a clear plastic tote/container that he put close to the back door. He attached it to a drain he installed into the floor. It was either a fitting or hose but it drained on the ground as he took a shower. Probably could put a bucket or water container to catch the shower water if needed. It did look bigger than the shower that FWC uses in the dinette area. I did a quick search for the video but didn't see it. Only draw back with his setup was you have to find a place to store the tote when not in use.
