Wow, thank you all for the quick and helpful replies.
I apologize if I skip anyone, all your help is much appreciated!
There are three kids in car seats. Two adults will always be present, with another 1-2 adults joining in at various lengths along the way.
I have looked into pop-ups, but it's basically a tent on wheels and I feel like it would basically be the same as setting up the tent and sitting inside it. I could be wrong though.
I'll be honest and say I have only looked into a few conversion vans, so perhaps there is one out there suitable for our needs. But the ones I have seen with seating/table areas don't have child-safe seating, or if there is enough seating/safety belts, there are no tables/bathroom, etc. That's the only reason I'm leaning toward a travel trailer versus an "all-in-one" so to speak.
I'm open to a full-size van, I just haven't seen any in my price range. It might be worth exploring though, so I do appreciate the recommendations to go that route.
This is something we intended to re-use, I guess depending how well the initial trip goes! :) We aren't looking for something to buy and re-sell in a year, and it wouldn't be a permanent home. Don't know if any of this makes sense. We prefer tent camping, but maybe that's because we've never done it any other way. I anticipate, being a complete newbie, that we would purchase our tow vehicle and small TT, using it to see the sights we can in the year. Then settling back home, and using it a few times a year to go on shorter excursions. We camp about once a month, but to take out the TT, we'd most likely be going on farther trips I imagine, so they probably wouldn't be as frequent.
Whew. Lots of information out there. Glad I joined now instead of a year from now!