A rare few have been able to actually get it out the front hood.
Note that the wood under the front desk is perforated for just that reason. There are several members on the forums here that added an access panel under the desk once they replaced the battery to make checking in on it much easier in the future.
I'd call Thor Customer Care and ask them, before cutting a hole in my dash. I've read posts on this and other forums that advised to get to it thru the right front wheel well but, as I recall, all said it wasn't an easy job.
Thanks for the answers! I did find a youtube video on it.
Would the wheel well be the route that a RV dealership would use?
I replaced mine going through the wheel well. Turn the front tires all the way to the right, remove the 4 bolts from the wheel well panel and remove panel... With the hood open, disconnect the 2 black vent hoses and then disconnect battery cables..Have someone lift battery out of tray and another person down at the wheel well to help guid the battery down and out...Piece of cake and took less then 30 minutes..Put new battery in the same way....