The bad news is that the rear street side of the trailer is rotted. All the way to about 10 inches inward along the floor and side. This necessitates me removing the floor all the way back to the first "non-rotted" stringer. This revealed a row of rotted cross braces that would have eventually caused the trailer to come off of the frame. This is why it is so important to do a proper restoration and remove all the rot, even in the framing. Otherwise you end up pouring a lot of money into something that will not last long.
In the photo below you can actually see the rotted cross braces that were hiding under the floor.
This photo shows both sections that are having to be cut out.
The water tanks were a great deal. $34.00 (U.S.). Available on Amazon by Class A Customs, who gave me great customer service. I was a little dubious about buying these, at such a low price and a couple of reviewers had indicated they were not that thick, so I wasn't sure what to expect, but they are thick and sturdy.
Here is the link if you are looking for them. I bought a 10 gallon and a 16 gallon for $34.00 each. They come pre-made with threaded entrances and exits for your pipes to attach to.