So you've got a Liberty like is pictured on the home page? Wow, rare bird! I think we were all fooled by your use of "van" in the original subject of your post, and thought you had some kind of conversion van.
Anyway, welcome to the forum
I can't speak specifically to your Liberty, but most of these trailers used parts that were available through RV supply companies (you can Google and then look through online catalogs). So unless there's something unusual (and there sometimes is!), you could get a water tank, for example, from any number of RV suppliers. Marine suppliers can be another source. Also, manufacturers such as Scamp
) have a parts department with some parts that are applicable to other trailers. www.vintagetrailersupply.com
also has some useful parts, and there are links over to the left in the "helpful links" section.
If you can show us photos of what you have and are asking about, we may be able to get more specific in our suggestions. Besides, we want to see your trailer!
Looks like a lot of nice wood inside