Welcome aboard scottychop...
"
Any young families our there that want to share their experiences with trailer design?"
to answer your question... You have come to the right place to find ideas and advice on a new build... There are volumes of information on the forum and you should be able to find something you like...
That was a beautiful shot you took in Jellystone; my wife and I made a trip through there in 2015 and I agree, IT IS AWESOME...

Good luck in your searching and there are many TD's that can sleep more than two, especially if one person is fairly small...
