I think you've already said it .. "because I want one". Doubt any other pro/cons will help. However, my folks bought a large 5vr years ago, new, for one of the reasons you list...grandkids. I know you said 5+ years away. Point is, my folks never camped more than a few hours from home and often had some or all grandkids with them. Always had room. So to me that was the reasoning behind their purchase.
If you want to go "easy" as you say, for ease of towing/hookups, might I suggest a Class C. You can find them all day long, new and used, and they have zero hookups unless you want to tow a car behind. If you did not want to tow behind, have the wife drive behind you for the cost savings, if you needed a dinghy. With a C, you can drive it to your campsite, back in, and done (minus electric hookup).
My 2 cents.