We pulled a 35' TT with a 2000 Excursion until and 200,000 miles I noticed she didn't like climbing the mountains. Needed to be doing 70 to be doing 20 when you got to the top. My kids grew up using the TT so we are empty nesters. I'm a Ford guy so depending on the size of 5ver you are thinking of getting I would recommend F250, F350 or F450 and you definitely want diesel if you want to keep it long term. Take your time and do your research. While the kids are young, don't rule out a Class C or Class A motorhome. Since you have the commuter cars, you could tow one with the motorhome. You can sell Ex and TT and replace with 1 motorhome.
Good luck! Thank God we live in a country with choices.