Transport Portland OR to Seaside

Three of us are arriving in Portland on 6-13 on Amtrak to begin a cross country ride. We need to get to Seaside. There is a bus leaving from the train station but we have one recumbent and possible that the bus shuttle will not take it. Have checked out renting a vehicle but no drop off in Seaside. Is anyone going that way with a pickup or trailer that would accommodate 4 bikes? Willing to pay.