<< What do you do with the bag when you get to your destination? Is it small/light enough to carry on your tour or do you mail it home?>>

My original Osprey Airport duffle packs quite small and weighs only 12 oz so I just carry it with me. I have even used it as a critter/bear bag by hanging it filled with partially empty panniers , food and miscellaneous gear while camping. The nylon is coated so rain is not a problem after I seam sealed the few seams.

The AirporterLZ- the latest model lists at almost the same weight-13 oz. I do not know how small the new model packs.