Leaving Dubuque - pt 2

I’ve been able to secure transportation for myself and my bicycle case from Dubuque to either Des Moines or Cedar Rapids (my choice) at the conclusion of RAGBRAI. My question is, how soon will I be able to pick up my baggage from the transport service and how busy/crazy is it at the end of the ride? Will it be difficult leaving Duque because of the traffic? I want to give myself enough time to get to an airport and make sure I book my plane trip back home (San Francisco Bay Area) with enough time so as to not risk missing my flight.

TIA