Just last year, we celebrated our parent's 50th anniversary at WDW at the Polynesian Club Level, & my mother is in a wheelchair. Without a doubt, there are rooms with roll in showers as well as other accommodations such as a small ramp to go to the patio & an electric door that stays open to allow coming/going. Just make sure and include a notation on your reservation that you'll need a handicap accessible room. We also never had any difficulty with Disney transportation from the monorails to the buses to Magical Express.
As for your celebration, the easiest thing to do is to get a free Anniversary button from Guest Relations at any of the parks. In fact, the Polynesian Concierge staff may actually have them, too. Then, include a notation in all your dining reservations & resort reservation about your special celebration.
If you'd like, you can do lots of special things such as a
fireworks cruise to celebrate or an
in-room celebration. The Concierge staff of the Polynesian can help make these arrangements by emailing Polynesian.Itinerary.Planning@disneyworld.com.
And of course, your anniversary dinner should be extra special. I'm limited on space, so if you'd like to send another question my way by clicking
here, I'd love talk about Disney dining for your amazing celebration & any other questions you have.
Wishing you an early happy anniversary! Please let us know if we can help again.