When driving to the airport, we just follow the signs to the relevant terminal (A or B) for our airline, and then once headed towards that, follow the directions to rental car return.

When arriving at the airport on a flight, we also just follow the signs to rental cars and then Avis. Strangely, I've always felt like we ended up at the same place whether we arrived in terminal A or B, but perhaps there really are two locations. I'm quite certain that there is preferred service at both locations, if there are indeed two.

The only sign for Preferred is once you actually arrive at the kiosk in the Avis area of the parking garage, and it is clearly marked. Although we've never stopped at the counter inside the airport, so I'm not sure if there are signs there, but presumably there would be signs directing Preferred members to proceed directly to the garage, or else a dedicated queue for Preferred members.

It should be quite intuitive once you arrive. MCO's a well designed airport and you shouldn't have any trouble.

Susan