Welcome to OSO Mike.
Finally, another F-206 owner!
You could try to retorque the bolts but I'd let a service tech look at it. The seal (O-ring) on the transom assy maybe bad. If so the drive, transom assy and possibly the engine will have to be pulled to repair it.
The change in altitude had nothing to do with it.
The long haul may have contributed to the cause.
Have it looked at ASAP!
Water seeping in will soak into the transom and possibly cause the wood to rot if not stopped. Sounds like it's in the water now. Get it on the trail as soon as possible and don't leave it the water till it's fixed.
Pick up a service manual and read up on your drive system. You'll learn a lot and understand what the service tech is telling you.
Best of luck.
Let us know what you find out. We're all here to help.