In April, my mom and I went to visit my sister, BIL, and their 3 kids in Florida. We went to MK on our second to last day there. My sister was VERY adamant about HAVING to have a family photo on the ride side of the castle where the stone wall curves into a bench area. To cut to the chase, she made me walk up first because I am the tallest and was going to need to be in the back, but when I turned around and no one else was walking up with me for this photo SHE wanted so bad, BOOM-- there was my fella standing in front of my family, looking happy as could be in a Toy Story t-shirt. We live in Memphis, and he even called me late the previous night to say he "made it safely to his cousin's house in Nashville for the weekend", when in reality he had gotten to his resort room at noon the previous day. We didn't have a photographer, but my family was there, so they took a ton of pictures and the Photopass CM caught a couple, too.
Anyways, it was beautiful and special. If you're set on proposing in a restaurant, that will be lovely, and I know she will be excited no matter what. The proposal was my fiance's first WDW trip (we ended up going for a big trip at the end of May), but this was great because it was a "private" little cove to where we had our own little bubble. Unlike proposals in front of the castle (WHICH ARE GORGEOUS AND MAGICAL AND AMAZING), we didn't have people walking all around us, but they were in the back of our group walking down the sidewalk so we weren't really bothered.
There are so many places you could propose to make it special. There are beautiful resorts, "quiet" areas to the side, or even certain rides! I thought my fiance was going to propose on our May trip (so I was EXTRA surprised), and I was imagining all different ways he would do it--at all kinds of restaurants, walking along the Poly, riding on Peter Pan (my favorite).
You can do anything, and anything you do will be magical and special. Good luck.