For a ride like this you should have an adventure or dual sport bike, preferably with some kind of off-road tires.
Adventure bikes are road bikes that can be ridden in the dirt. They have taller suspension, higher ground clearance, and a more upright riding position than most road bikes. On the other hand, they are heavier, more powerful (650-1200 cc), and more highway oriented than dual sport bikes. Adventure bikes can easily handle forest service roads and reasonably well maintained gravel and dirt roads like we’ll be riding on this trip
Dual sport bikes are dirt bikes that can be ridden on the road. They are smaller and lighter than adventure bikes, have even taller suspension, spoke wheels and a larger front wheel, and usually wear knobby tires. Although they are street legal they aren’t well suited to prolonged highway riding. They are easier to handle in difficult terrain and easier to pick up than adventure bikes.
All of us but Coop have adventure bikes – 650 cc up to 1200 cc. Coop loves his little DR 650 on the gravel, but not so much on the highway.
Although we are all members of the BMW club three of the group are riding Suzukis. It smacks a bit of disloyalty to the brand, especially since BMW invented the adventure motorcycle segment in 1980 with their introduction of the R80G/S (Gelande Strasse, or offroad/street). But, hey, we are an eclectic bunch so we didn’t make an issue of it.