a little confused about the timeline, but seems you're okay getting to the first hotel.
you'll take on the train: bike, on tour stuff, and before/after tour duds.

in that case, after the first few days, you send the dressy stuff for after the tour
by ups to your next hotel, in a duffel or small soft luggage.
you leave the hotel on your bike with only the stuff you need on tour.
you have all your on-tour needs in two bags, which just happen to be bicycle panniers.
you do not need duffels or backpack on tour.

when you finish the tour, you leave the dropoff point by bike with your on-tour stuff inside
the bicycle panniers hanging on your rear rack.
your dressy duds are waiting for you at the hotel.
you may at this point send via ups one or both of your panniers home.

for non-riding days, i wear my gettin'-to-another-country-goin'-thru-airport-clothes.
lightweight cotton/nylon khaki shorts with elastic waist (no belt=no buckle=no tsa)
lightweight no-iron quick-dry polo-style shirt.
tevas/sandals (no take off ze shoeses at security) and a soft cap.
no belts, no zippers, no keys, no buckles, no metal whatsoever.
all of this, except for size 12 sandals, folds up really small, and really light.