Tourist in MSN
For luggage that you can carry everything in except the bike, consider a large duffle type sack. But, I would send the racks with the bike because you do not want anything that is too crushable in the duffle.
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Large lightweight dufflebag works well. Empty Panniers, helmet, and water bottles go in box. Also, the racks go in bike box, even though they may need to be taken off the bike to fit. Contents of my 4 panniers and camping equipment is divided between the duffle and my rackpack. The duffle goes as checked baggage, and the rack pack with the more fragile items, and the bar bag go as carry-on luggage. The duffle (large yellow bag), weighing about 5-6 ounces is carried in the bottom of my panniers until the return trip.
The black and yellow duffle bags hold 6 panniers worth of gear. The rackpacks hold the camping gear when on the bikes and bar bags hold valuables. Only 3 bags per person to deal with, 2 of them are carry-on. This was for Amtrak, but we have used the same system several times on tours requiring air travel.
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