I have a 2011 Sienna and I cannot recommend it highly enough! One thing I would really look at/for when getting to a bigger capacity vehicle is access to the the third seat and hopefully moveable second row of seats! I had to rent a van while my Sienna was getting a booty lift (minor hit and run to the back bumper) and I was having so much trouble with the 2016 Town & Country because the second row seats don't move. The law here in California is that babies have to be backward until they are 2 and the Pediatricians all recommend longer if possible. So, my son who is almost 4 is rear facing, as is my grandson at 1.5... This means I have a car seat behind the passenger and the driver, but it wouldn't fit in the T&C without moving the driver seat forward, which means you either drive super uncomfortably OR you put the baby in the 3rd row. I ended up folding one of the third row seats down, and putting the baby in through the trunk, which is a hassle...
SO, if you can, bring a rear facing carseat to see how that works (they can be quite large!) or at the least remember that your grandbabies getting in and out is going to be a factor and climbing in through the trunk is not always a fun way to go!!
Huggles!!
~Sarah~