Used 2022 tiffin 34k 35’

Considering this coach.  Will be our first .  We have always mountain camped in 5th wheels but are going to start doing cross country traveling .  This coach has the 340 Cummins diesel and we’re a little worried about going over mountains .  But in my research I discovered slow but should be fine as long as we follow weight recommendations ….. anyone out there with any thoughts or advice on this coach or engine would be great ….. thanks in advance …