Meaning... a perp worth his salt, with a boat, would have dumped the bike in the water.
Sooo... assuming the bike has been there since the night of the abduction..I see a hurried exit from Lafayette, a pullover 25 minutes later at dark Whiskey-Bay exit to sort things out (maybe secure Mickey better) and a hurried run into the bushes with the bike, and then peel out down I-10 heading east, with Mickey, w/o the bike.
OR, Mickey held somewhere and the bike disposed of... but why? If she's held somewhere, why not keep the bike?
Again, if they had a boat, the bike would be in the water and not found. So..... this looks like "dump the bike and split."
Crucial is going to be whether the police had already searched the area and not found the bike. The timing of the bike's appearance is critical.
What I don't want to think about it if Mickey and the bike were left there at the same time.