Around the entire US in 2 weeks? Not enough time. You are not going to see much but highways and hotel rooms. 2 weeks in the west and 2 weeks in the east would be a minimum I would think. My wife and I have probably spent 2 months just travelling in the west and haven't seen everything we wanted to see. There is a lot of space between things out west. Maybe if you are just hitting certain highlights...Pacific Coast Highway, Glacier, Yellowstone, Tetons, Grand Canyon, Rt 12, Beartooth Pass, then head east ... it takes a good 3 1/2 days just to go from there to the Smoky Mountains and BRP, Dragon etc, then to Key West?. Wow, a lot of saddle time for sure.
I agree with Redfish. As far as the rear tire lasting. Gosh if you started on a brand new premium tire...maybe, but I wouldn't count on it. Watching those last couple of mm wear away each day will wear on you mentally. It doesn't take long going from" that doesn't look TOO bad, to dang, where did those cords come from?" Especially on the rear. The worry will zap the joy from the last part of your trip. I too plan trips pretty carefully and always allow at least one day for "emergencies" in my trip plans. That could be mechanical or weather related or just eating some bad food at a restaurant.
I plan on 6,000 miles on a trip tire (even though it will probably go more). Weight, heat, pressure and road surface as Redfish mentioned are the enemies of tires.Too much weight, too high of speeds, too low of tire pressure and rough roads will eat tires up.
Redfish's pop got great mileage imo. Using less than half the available tread in 5800 miles. Tells me he is not too hard on the gas or brakes and not that aggressive in the twisty bits. He is undoubtedly a very smooth rider. If you can emulate that you might make it on one tire. If it were me I'd also have a back up plan in case a tire was needed on the way home.
2018 Yamaha FJR 1300A
2014 Honda CB1100 DLX
It doesn't matter what I ride, where I ride, how fast I ride, or how far I ride... it only matters THAT I RIDE...EVERY DAY. "Ferret"