Hi Mr Roberts95. I don't know anything about Duke trailers, but wanted to welcome you to iRV2. Check out our Vintage RV section - you can probably get some tips there.
There isn't much difference in most RVs - just trim and styling. A travel trailer especially is juts a box on wheels. Appliances, water systems, etc. are pretty much industry standard items.
2004 American Tradition; 2014 Buick LaCRosse
Homebase in the Ocala Nat'l Forest near Ocala, FL