Look over the specs carefully. I've seen TT's with holding tanks that if FULL would put the TT over GVWR. There's no point having holding tanks that you can't use safely. I would recommend figuring out how much cargo capacity remains if all tanks are full.
Also take 'specs subject to change' seriously. My TT specs said it had a 12 gallon black tank, the tank itself had 10gallon embossed on it. I found out the manufacturer de-rated it to 7.5 later, but what it actually held was 6 gallons on a good day.. and that included 3' of 3" pipe!
IMO kids are going to eventually want their own space, consider tents if possible.
Take your time! Learn about what all the weights mean for both TT and TV, it'll be a process exploring what's available. In the end the more you understand, the better you'll be able to make educated decisions.
