We just rented a premium for our beach trip last week. It was dh and I plus our 3 kids, my mother and my sister (who lives in FL). We opted for the 8 seater since we were not sure if my BIL would be joining us and I think he did one night for dinner. Last year by Luck we got the premium and it fit us so much better so we opted just to rent it this year. Previous years we had a van which I drive at home and it fit us but beach chairs were not always fun to load (7 of them). This was just more roomy for the amount of us. I’d go smaller if I could.
If price is no object then rent it, it is nice but I think it is more room then you need. We averaged about 20mpg but we did lots of highway driving-like 1200 miles, which is why we wanted to be more comfortable with the bigger rental.
So we had 6 suitcases (the kind we can use as a carry on) and the huge LL Bean rolling duffel plus 6 carry on sized bags/back packs and that all fit in my van with the 3rd row up-dh, me, our 3 kids and my mOther to/from the airport in CT. If you only have 2 kids you can stow the seats and have a bunch of floor to ceiling room for your drive to/from the airport. The same set of luggage was in the suburban and it fit as well.
I would choose smaller SUV or a van.
