The two times I have flown domestically for unsupported tours, I have shipped my bike via UPS in a plastic case from Crateworks:
The boxes are big but still "airline legal." Their depth allows me to fit both my large racks in the case along with my 60cm LHT. I remove them and "weave" them around the frame. I also put my stove and empty fuel bottle in the crate. I ship the package to a local bike shop at the start and have them assemble and tune the bike. The shop stores my box and the duffle bag I flew with. When I return, I take the bike to the shop and go have a beer. The shop packs and ships the bike back to the address of my choosing. The shop labor costs money, but if your airline charges a lot for a bike, youi might save money or at least break even. Plus, you don't have to worry about ground transportation with your bike if you don't plan to ride straight from the airport.
I am booked to Missoula in June on United. I think United charges $175 for a bike each way. I will be going the shipping route again. If you choose to ship, you should leave about 10 days for UPS ground shipping just to be on the safe side. I have shipped from Philly to Montana twice. It's never taken more than about 7 days, but I like to play it safe. Also, you should make arrangmentas with the shop well ahead of time so you will be on the schedule. A few years ago, the Missoula bike shop we used forgot to put us on the schedule for packing and shipping back home even though we had made it clear when we would be dropping our bikes off. That resulted in about a 4 day delay in getting our bikes back.