[RMcNeal]

Your hose is definitely too short. I can vacuum the couches in the rear den and all the way to the closet in the main bedroom with ours. It's also a 3791RD with the vac below the steps to the bedroom.
We tend to use the toe kick dustpan more than the vacuum, though. It's just easier than dragging that hose all over, and the dogs don't freak out as much.