Ok, I did the wheel well modification this afternoon. It went relatively smoothly thanks to the instructions and helpful advice provided to me by Hal Swanson and others.
Some comments/observations...
I have a 2001 2720SL. I’ve had some six other trailers before this one and this is the first I’ve seen with square wheel wells. What were they thinking? At any rate I took the covers off both sides first to see what needed to be done. I had precut the sheet metal with three tabs. (A good pair of tin snips and gloves are essential. Bring them with you to the trailer for necessary modifications). The first thing I noticed was that on the “kitchen” side two drain tubes came through the floor just in front of the wheel well. So I had to trim the sheet metal to fit around and in between them. And on the door side there was another tube (for what I wonder? It had no valve like the drain tubes do)just behind the frame member. To raise the body (after removing the lag bolt) I used a hydraulic jack and a piece of 1x12 to spread the load out. I didn’t want to focus the lift on one single point. I raised it a little bit at a time and used a piece of scrap sheet metal to test clearance. A gentle tap with a hammer on the frame helped to break it free from the body. I used two drills. One with a bit to make the holes and the other to drive the sheet metal screws. Have something to mark the sheet metal with since you’ll no doubt have to do some last minute cutting. 48” was too long on the door side where the latching mechanism is located. But trimming was no big deal. I wouldn’t say my curves were a thing of grace and beauty, but I expect they’ll to the trick. To fill the voids I used (so far) two cans of minimally expanding foam. There is minimal expansion and greater expansion foam available. I felt that the minimal expansion would be easier to control/regulate. I ran out, but had filled one side and about half of the other. I had to leave the trailer set up so that the foam wouldn’t come into contact with the trailer sides while it is setting up. I’ll go back tomorrow and finish up the foaming. By the way, I found the back bumper (in particular the aluminum cover over the storage area) to be more than adequate for bending the sheet metal. Total time today was a little over three hours. I tend to work at a deliberate pace (I really hate to do things over) so it could be done quicker I expect. In sum it was not a particularly difficult job, which was greatly aided by having the right tools and plenty of good advice and instructions.
An engineer friend of mine suggested plotting out the curve ahead of time and cutting styrofoam pieces to fit the voids. Stick them in the corners and then curve your sheet metal perfectly he said. That would probably work too.
At any rate, I’m glad that I did it. We’re off to Yellowstone after the holiday so that is one less thing to have to fret over.
Thanks again for everybody’s help and advice.
Jim