I would choose the Grand Floridian first, CR next and WL last.
The Grand and the CR are on the monorail line and that is of the utmost importance to us. You can't beat the convenience and the views from the monorail resorts. We stayed at WL once and were quite disappointed with the boat transportation. SLOOOOOW!
I would almost vote CR, but the rooms are in need of renovating - and they are doing just that as we speak. I've seen pics of the new rooms and they look fabulous. If you are going when the renovation is complete, I would probably pick CR over the Grand.
WL is a beautiful resort, but most of that beauty lies on the surface. Meaning, the lobby and exterior, and the grounds, are breathtaking. The rooms leave a little to be desired. They are small and dark. And, IMHO in need of repair. Although WL is a MK resort, we felt far removed. The bus transporation left a lot to be desired. However, we loved the geyser and the trail to FW. I wouldn't call our visit to the Lodge a bust, but it certainly isn't a resort we're clammoring to go back to.
The Grand is, well...GRAND. But, a tad stuffy for our taste. But, the rooms are beautiful, the CMs are top notch and there are great restaurants to choose from. Again, if CR's rooms are renovated by the time you go, I would pick CR over Grand. Simply because of the stuffy factor.
Our favorite MK resort is the Poly. In fact, it's our favorite resort overall, followed closely by YC/BC. You didn't have that one down as a choice but I would think about it. It's the #1 resort for convenience. Not only do you have the monorail to MK, but it's a short walk to TTC where you can hop on a monorail to Epcot. The landscaping is so wonderful and the volcano pool wins the best MK resort pool contest. The CMs are great, the food choices are excellent. Think it over - you might just want to add the Poly to the list.
Have fun whatever you decide.
PamNC