8 of us just got back from a Detroit to Los Angeles, and back, trip and I can tell you that you want to stay on the major interstates. First, there are plenty of Harley dealerships off the major interstates and although most of us had brand new CVOs, we ended up needing several dealers along the way. We all fueled up in Lebanon, MO at a Phillips 66 station and all of a sudden 3 bikes wouldn't even start. Turns out the gas tank was full of water. The station refunded all of our money and paid for the Harley dealer to drain all of our tanks and put new gas in. That dealership happened to be 1/2 mile away. Second, the gas stations out west are very far apart. In fact, on I-40 in California, you have to fill up in Needles, Ludlow and Barstow because the stations are 80 miles apart. Miss one and you might not make it to the next one. Also, road service and towing is very sparse out west, as.
Another bit of advice is timed gas stops. Don't let everyone be on their own agenda or your stops will take forever. This wastes a ton of time. You want to try to do all of your riding during the daytime hours, because the animals are all over at night time, especially in the mountains. A club brother of mine just hit a deer in California on Thursday. He is OK, but bike is toast.
I can tell you there is nothing like traveling cross country on a bike. We are doing Seattle next and then back to Cali.
Enjoy!
KB