The 670 is a "condo" truck with a 60 inch sleeper on it. The only "issue" with the sleeper is a lack of storage space, but you can over come this if you are a solo driver and just use the top bunk for additional storage.
The truck is very maneuverable and you can easily crunch cab fairings if you are not careful. It is very easy to drive and very comfortable to drive.
As far as power goes that all depends on what it has under the hood and what the specs are for the tranny and rears.
Pretty much any of today's trucks though can pull the hills out west, though you may be down to 15 mph by the time you get to the top.