I've had a few different bikes in my time, they are ideal for when there is nothing to do. I've just got rid of a xr600, that was a animal but i'm happy with the yzf at the minute, i'm thinking of a wrx426 enduro for on and off road
If your going to let someone take your dog out make sure you can trust them completely as lurchers can have accidents far to easily, i used to take my mates dog out but if it got injured i would phone him on the way back to let him know and to make sure he was awake when i got there, so he could check for himself wether it needed to go to the vets or not