It depends a little on which building you are in. In Sept we were in Conch so it was a slightly longer trip to where the walkway starts, but it’s no more than a couple of minutes difference. For front of pack at EE I like to be at the park 1 hr to 45 minutes at the absolute latest depending on when they start letting ppl through security. I’ve noticed MK tends not to let ppl thru as early as the other parks but walkers still have an advantage.
Depending on how fast you walk GF to MK is about the same as the walk from Swan or BWI to HS I find. Around 10-12 minutes but I walk fast lol. But I also love that walk because it’s really quiet and beautiful in the very early morning hours. We even saw a stag at the edge of the trees the morning we did it!