My husband suffers from a condition similar to CFS and uses a mobility
scooter. I highly recommend renting a mobility scooter. We bring ours from home (your airline will check it for no charge as a medical device) or there are companies that rent them on the island. There is a beach wheelchair if you need that assistance getting onto the beach.
The hotel is new, so it is fully accessible. The only issue we ran into is getting to Roy's and Monkey Pod you have to make sure to exit the hotel and go through the parking garage to get to the elevator and take that down to the street/sidewalk. The walkway down the entrance drive aisle is not accessible (no real ramps, just roll curb).
You can participate in all the community room classes like learning Ukulele, animation, art tours, and the menehune adventure trail with the ipod things.
My husband also liked stopping at the food trucks and then going to watch surfing on the north shore. He LOVES Hawaii... some day he would like to move there because he feels he has found his happy place. In Hawaii it is a perfectly acceptable day to go watch other people surf. No pressure to actually be the one surfing. It is a wonderful day just to sit and listen to the waves. No need to actually be in the water and splashing around.
Since my husband tires easily, we did not venture many places. We did tour Pearl Harbor (fine with a scooter). We also did the swap meet one day with the scooter for a couple hours and that was fun.
Another fun one is to try a horseback ride if you find yourself with enough energy one day. It is still tiring, but if pretty relaxing since the horses just walk nose-to-tail at a slow pace.
You will love it!