​​​​​​I flew from Gatwick to Orlando with BA and arrived in Terminal C on Dec 15. I needed to get to terminal B to access the rental car garage.
Outside, I found roughly 150 people waiting for the "shuttle". I waited about 20 minutes until it arrived - it was in fact a long distance "tourist" bus! Obviously only a part of the crowd were able to fit in and it took ages. There were people in wheel chairs waiting to board the high bus with stairs and the helpless driver was frantically putting luggage in the cargo space.

I ultimately took an Uber from one terminal to the other, paying about $30 for the trip. Ridicilous.

It's obvious that the infrastructure is completely inadequate at the moment. Traffic around the terminal was severely jammed even though judging by the amount of people inside, it wasn't that busy at the time.

I hope they are building a train system between the terminals as that seems the only reasonable system to run traffic between them.

On the plus side, baggage claim and customs was fairly fast, though as said, it wasn't super crowded.