The route you've posted takes into account the suggestions that many of the posters here have given you. It avoids most tolls (especially important with your multi-axle rig), and should be scenic and relatively stress free.
There are still a couple of final elements to worry about. One is timing. To make this an enjoyable trip, you'll need at least seven days. That will give you time for a few short breaks each day to get out and walk around, and/or to just sit out any nasty weather you encounter.
The other thing to think about is accommodations. While most highway-side motels will have some provision for pull-through parking, not all will. So you should have some methods (GPS, AAA Tour Books, chain directories) that list motels along your route so that you can call ahead to check as you work your way down the road. You probably shouldn't make reservations days or weeks ahead, flexibility will be a key in this trip, but rather start calling when a couple of hours out and are pretty sure of where you want to bed down that night.
Have a safe and enjoyable trip.
AZBuck