Campman,
We have a 2406 T and have had a problem very similar to yours. I am going to provide you a couple of links to refer to on how a couple of us handled the shroud problem. I'm sure your shroud, like mine, is a plastic shroud, which Hi Lo used in some 2000 models to cut back on the expense of a fiberglass shroud that they normally used. Maybe you can get some ideas from several of these posts.
http://www.hilotrailerforum.com/f17/...1583/#post9885
Take a few minutes to go through this series. While it is mostly about our roof repair, there are some pics that show how I removed and replaced the caulking on the end caps. I would suggest that you check your roof out and make sure you don't have the electrolysis problem that some of the Hi Lo's with metal roofs have experienced; again, due mainly to poor workmanship when they applied the roof.
http://www.hilotrailerforum.com/f25/roof-repair-1685/
Due to the age of your Hi Lo and the similarities to ours, you may want to give your windows a real close check. The factory used a very poor butyl tape and oftentimes some other gooey stuff to seal the windows. Most wall damage is a result of leakage around the windows so you may want to review this as well. It is not as difficult as you may think. Check the posts here:
http://www.hilotrailerforum.com/f36/caulking-tip-186/
Good Luck on your end caps.
Jerry Curtis
2406 T