That works perfect if you don't have to load or unload. For me there aren't many days where all I do in the 14 is drive.
I agree though, it's a good idea to get out and stretch your legs every few hours.
A lot of guys has stated that it is good to stop, walk around, etc.. I do the same, and I'm a local (line haul) driver. I always try to stop, and walk around my truck, trailers atleast once (I run a 400 mile round trip). It's not good to sit for hours and hours at a time. Not good on the prostate, or atleast that's what I've heard. Good thing rakusa that you use the rest room often. It gives you a chance to check your loads, and stretch out.