I am in the same boat as you. Just picked up a new puppy this past Saturday morning, but I will probably leave him at a kennel here at home. Some of the trails we will be doing will be smooth, but most of them have some amount of jarring obstacles on them. There are a few obstacles on a few trails where anything that isn't nailed/strapped down in the truck will end up in the foot wells because you are headed straight down. I don't think it's fair to the dog (and I'm speaking about mine here) to throw him around in the truck all day. In the worst case he could get hurt from some of the violent shifting the truck will do. There is a nice kennel in town that some have used while out on the trails. They will have to chime in on that though.

The big thing is that some of the trails are on government land and no animals are allowed on them so you would HAVE to kennel your pup or leave him behind.

All in all, for me, it's just too much to bring the pup and all of his stuff, plus my stuff, plus the girlfriends stuff, plus the bikes, plus all of the tools for the VX, then find a place for the pup if I can't bring him on the trails or want to go mountain biking for a while.

Just my two cents.