Hi!
Please tell your Dad that we have stayed at POFQ many times with my personal
ECV, and I have no problems at all. We push the table and chairs into the corner, and I bring along a heavy-duty extension cord to be able to charge the ECV battery easier. At POFQ, I typically plug in to the electrical outlet that is on top of the dresser/fridge cabinet. Remember to charge the battery every night, regardless of how far you went that day. Last thing you want is to be stuck with a dead battery while everyone else is having fun!
If he needs or wants more space, after he checks in, he can request that they remove the table and chair(s) from the room for the duration of his stay.
He might want to bring along a door stop to help hold the door open while entering/exiting. Doors at WDW Resorts "self close" (for guest security) so trying to hold it open with one hand while going in or out can be tricky. Because the doors at POFQ open to the outside world, they have a bit more of a bump over the threshold, and you do have to make a turn directly after entering the room to avoid hitting the bed!

If he can "walk" the ECV in and out of the room, it might be easier.
There are elevators for the buildings; POFQ is (relatively) small, and very easy to navigate.
Your dad will find that he can easily take the boats to and from Disney Springs at POFQ. It is one of our favorite things - I love that little trip up and down the Sassagoula River! The boat captain will place a ramp for him to drive on to the boat, and at the end of the trip, he will place the ramp again to drive off. Most of the boats at WDW are ECV accessible (with the exception of the little launches) as is the Monorail.
One tip for a first-timer: At the bus stops, look for a white painted rectangle on the ground. If there is no other wheelchair or ECV user in that box, he should park in that box - the bus drivers look to see if anyone is there. ECV users always board first, but exit last from all transport at WDW. Drive straight up the middle of the ramp, and be prepared to turn right at the top of the ramp to park the ECV. The driver must tie the ECV down. Anyone traveling with your Dad can board the bus with him at the time his ECV is loaded. Always listen to the bus drivers (and boat captains) - they will be very helpful!
I predict he will love POFQ - Laissez les bons temps rouler!
