Our pitfall was the joints, no doubt about it. Probably the weather conditions down here caused it, but we ended up using some bondo, some sheetrock compound, and gorilla tape on every seam. What worked for one station didn't necessarily work for another. Tonight I get to repaint all six stations and have my fingers crossed for them--even though our camera operators say it won't be noticeable.
Funny you're using buckets. When I built my small Classic Trek bridge for the 10" characters, I used large,styrofoam, Chick-fil-a cups for their chairs.
But you're right. The construction being done at the same time is incredibly mutually beneficial.