I put some clear Command decorating clips right under my awning, on the side of the trailer, that I hang 2 strands of solar lights from. I have had the command hooks on the trailer for about a year and have only had to re-install 2 so far, and that was because I yanked on them.
You can do it, just take it one step at a time. Take pictures as you go along so you know what goes back where when the time comes. First thing you will need to do is locate where the water was coming from and fix that. If it was any of your holding tanks they can be repaired and/or replaced, depending on how much you want to put into it. You can rent a lot of power tools you may need at your local Home Depot, or ask a neighbor. Don't be afraid to come back here and ask questions, there is a lot of experience here on the forum. Post pictures because they are always very helpful , as each project is a bit different. And if all else fails you can call a mobile RV repair person to fix it, or at least get an estimate to repair it so you can wiegh your options.
We were looking at older Airstreams also, until we went into one and it actually felt too closed in for us. We imagined it raining outside and trying to fit our 2 grown sons and us in it comfortably and changed our mind. I then started researching Avions and went into one and was surprised be the amount of room it has. So we now have a 1978 Avion 30'. The cabnitry and flooring are built very well, and with a rear bathroom there is plenty of room to move around. Ours has 2 twin beds and a sofa bed that we plan on replacing with a dual reclining sofa soon.
So I would suggest spending some time in a few different types before jumping in with both feet.