I’m having a logistical issue with Hoop-Dee-Doo. Our first two days are at POR. We have a 6:15 ADR at HDDR on November 26th. This is our arrival day so we will be hanging out at Disney Springs. Can we take a Disney bus or Uber to Magic Kingdom and ferry over to Fort Wilderness? Can you use the ferry without actually entering the park?
Any ideas on the best/easiest way to get there is appreciated. This is our very first trip. 
Welcome to Linerville. Specifically, you can take a bus to MK and then a boat to FW without entering MK. A faster trip will be a bus directly from Disney Springs to FW. There are Disney buses that go directly to each hotel from Disney Springs at no cost. The best way to check on the fastest way to get places in and around Disney is www.ourlaughingplace.com. They have a travel time calculator on the website.
Also, if your kids are young, it might be tough to drive up to Magic Kingdom and not go in. I know the first time DD4 (at the time) saw Cinderella’s Castle she was so excited. If we told her that we weren’t going into MK, she might have disowned us.
Just made this trip a little over a week ago on our trip. We bused to MK and then went with the boat to Fort Wilderness. On the way back, my boys decided to have a race. My oldest and I rode the boat back and took a bus to our resort (AKL). My youngest and my wife took the bus from Hoop-Dee-Doo to the front of FW and then bus to MK, and bus to AKL. Your results may vary, but I got a text from my wife which was a pic of them in the room while we were boarding the bus in MK.
I would take the bus to MK and ferry to Fort Wilderness. It is just a short walk from the dock to the HDDR.
I believe this is the easiest and least confusing for of transportation.