HELLO !
Where in Va ?? I grew up and have family in the shenandoah valley.
We lived in Stephens City for a few years - and i worked & lived all over the Northern Va area for many years.
POWER is good....more is better & you can never have enough
4
KIDS and 2 big dogs in a 31 footer is
tight....we traveled w/ 3 teens and an old english sheepdog...the kids are almost out of the house (one lives in winchester, on in flight school / pensacola & one is a Sr. at Tx A&M)
Sounds to me like you're looking at a 45 foot coach w/ bunks...and the added 6" (optional) roof extension would be nice for the kids who sleep in the bed space above the drivers cockpit.
when you go to a 45' you're looking at a 2nd drive axle (w/ duel tires)...
advantage: safety - brakes, traction (being able to lock each driven rear axle diff independently or together is nice), tires (n the event of a flat), towing - you'll probably NEVER exceed the weight limit, slightly reduced mpg.
disadvantage: tires (assuming 700 each, means nearly 3k on cost for the extra rear axle), maintenance of the 2nd axle brakes, airbags etc, weight might need to be manages since you're missing that 2nd 20k lb capacity axle.
but lets face it we're likely never to need to add brakes & tires might only wear out by AGE not mileage.