Making a longer travel trailer?

I was wondering how i would even start to make a longer version of the travel trailer. Im sure its way too hard for me to do but how do i even start. And is it possible to do without creating a new j beam?

 

You could model an extra part and slide it in to the travel trailer, and you don't ahve to create a new jbeam for it. Just edit the older one

 

Maybe I could make a mod like that if you gave me details and stuff on how to do it. Again, do whatever you want.

 

Appesh1, I might watch it later.