Hey, I have a couple of thoughts related directly to your question and some not. First off, minivans are great camping vehicles. They usually have V6's and can tow quite a bit! They carry lots of gear on their own.
Now, without sounding like a True Scottsman, I'm not sure I understand your reasons for a pop-up. There are different types of camping and comfort for sure, but your suggested reasons for getting a pop-up aren't super FI friendly. I want to preface one more time; I'm not trying to gate-keep, just trying to offer alternatives.
First of, for camping with kids, they love tents. Kids are robust young ones usually take well to the outdoors (it is quite natural to run around, piss on tress, build things out of rocks, and look at birds so the freedom of it makes sense to them). Pop-ups usually incur significant costs. They must be maintained and registered. They put more wear on your vehicle. They physically limit your camping locations. They must be stored (this might not be an issue for you). Overall, you are paying significantly more for equipment that you use occasionally.
I camped in Arizona for 10 years while I lived there (is that the snakes and scorpions territory that you're talking about?). All you have to do is keep your tent zipped up. It's only very slightly harder than having a raised pop-up in terms of keeping out the critters.
For long road trips and explorations, you can do a *lot* with the money saved from not owning a pop-up. If you take a week long camping trip, perhaps spend one night at a hotel or AirBNB to shower and recover. That costs $200 max, compared to the $4K you'd spend on a pop-up, not counting the other costs. You could do that a minimum of 20 times, conservatively before even getting to the cost of a trailer. Assuming you get an airBNB 4 times a summer instead, that's 5 years of camping with a luxury stop before a conservative break-even cost, and that's with heavy assumptions and zero maintenance cost assuming the family holds interest for 5 years.
I'm not trying to opposed the idea of pop-ups. They make a lot of sense for someone like my parents who have a hard time sleeping on the ground now. They are also good for folks living for significant portions of the year in a vehicle, such as a seasonal park ranger or the like. Or you just like them and camping in a tent kills the trip for you. But I think half of the fun of general camping is to do a lot with a little. The experience is in blending into nature rather than bringing a fold up house to it. But that's a personal preference/philosophy and is understandably not for everyone.