I'm doing the same thing Pete and in the same general time frame. (You'd be welcome to tag along with me, but I'm taking 2.5 weeks and am heading NE up to Pennsylvania to visit family/friends and coming home across the N US which I doubt is very interesting to you. I fly out Sept 19th and will take delivery on the 20th.)
When I was planning on a direct route back, my general ides was to ride SW through the Hill Country, then over to Big Bend and do a big loop of the best roads, then across S NM to near the AZ/NM border, head N along the border (e.g., the Devils Highway) to the four-corners area (this is the area where they've had some terrible fires, so might want to check for road closures or continued problems in this area), work my way through Escalante/Boulder/Cedar City area of central Utah (doing the Bullfrog Basin Lake Powell ferry and the Burr Trail if the weather was good), and wrap up by coming home through NE Oregon. These are all areas I'm pretty familiar with and all have great riding - if you want the best riding, this strikes me as the way to maximize it. And given the time of year and heat, I don't think you want to spend too terribly much time at low elevations. or in midwest humidity.
If you'd like more detailed route advice, drop me a PM and I'd be glad to help.
I'm probably just going to carry a Yamaha filter and do the 600-mile by myself somewhere along the way. Most car parts stores will let you drop the engine and final drive oil in their parking lot and take the old oil back if you buy oil from them. If you prefer to use a dealer, Tony may have some advice on dealers about 600-miles away. While I'm not planning on beating on the bike initially, I personally don't think doing extraordinary things during break-in or early/extra oil changes are justified.
- Mark