Newbie question

Hi all road warriors. We haven't hit the road yet as one of us hasn't retired yet but it's coming fast and personal stuff sales going good. The question I have runs like this, We are looking at a class a and then a trailer (enclosed) to pull our car around. Now I know there is talk about over packing an RV so I am wondering about the trailer. Not like we will have a ton of heavy stuff to haul but how does the tongue weight and the RV weight come together??
Thanks,
/-/oth and Sue