The iRobot Create has arrived. It looks pretty durable and steady. The AVR butterfly will swim in the cargo bay.
The first thing I've noticed that I'll have to deal with is that the Cargo DB-25 connector supplies 5vDC (TTL) for serial communication. The butterfly has an RS-232/TTL level converter on board, so they are currently mismatched.
I'll either need to route around the butterfly RS-232 level converter or bring the Cargo connector up to RS-232 levels (blech). Temporarily, I can use Create's serial cable (which plugs into a side mounted DIN) -- it has a built in level converter.