Hi John,
I've stayed at the Polynesian Resort once and will say that it is gorgeous! The "view" decision is all subject to personal preference, but personally I prefer to keep more money in my pocket and opt for the Garden View.
The Magic Kingdom sits across the lake from the Polynesian, so the view is a distant view of Cinderella Castle. As for transportation, you will have to take either the Monorail from the Polynesian's Great Ceremonial House or walk to the Transportation and Ticket Center and take the ferry boat from there.
One of the best websites for seeing pictures and maps of the resorts is
www.allearsnet.com. I suggest you check out all of the photos and resort map to help you make your decision. We stayed in the Samoa building and loved it's proximity to the pool and Great Ceremonial House.
You can add a building request to your reservation, just keep in mind that they are not guaranteed.
Hope this helps!