I know there has been some discussion on this topic and it's been frustrating to a few of us looking for options. I decided to tackle the job myself and am very happy I did. I hope it is ok to mention a facebook group for TAGS (T@G your it). I posted pictures there because I don't know how to downsize them. I hope they might help others. I am not a seamstress by any means, but I have done a little sewing for the house...straight line stuff. My first trailer project was adding a door entrance that attaches off of a shower/potty room. I used elastic around the door to hold it on. We finally used it our last camping trip and it was wonderful. Complete privacy and a changing room that would fit on most any site. The size is 3.5x7 I believe. Since this worked so well I decided to do the same with the ARB Deluxe Tent room with the floor. I cut out the zipper and tent panel next to the door and cut above the flooring material at the bottom...then I sewed it back on, attached the tent and T cut a hole for the door. I used an rei soft waterproof tarp for the entrance into the trailer. I used heavy round elastic (first one was too wimpy) which I made a pocket for (like a curtain rod) and slid the elastic through it. I did 1.5 times the door dimensions. This makes the seal around the door. I put the tent in place and pinned the size I wanted for the entrance. Sorry no pics here. I hope this makes sense.