If you're only going to visit to look around, the walk might not seem as bad because you'll only be doing it once. But yes, if you are staying at GF and using your car at all - valet all the way.
I think we made one trip to the self park on our first stay at GF when valet was still free for resort guests. I was young and stingy and didn't like the idea of spending money on a tip for the valet. I got over the $1 or $2 it cost after the one trip to the self park.