I would say that if you're not getting a cart it's all the more important to request a specific loop. But you need to consider what activities you are going to engage in the most. If you're going to be a park commando, the only loop that is within "reasonable" walking distance (good bike ride) to the Outpost Depot is 1700: there is a path from 1700 that shortcuts to Fort Wilderness Trail. If you will be spending a lot of time at the pool, tennis, campfire, or pond fishing, loops 600, 800-1100, 1300-1600 would be the most convenient. If you will be touring the Magic Kingdom alot, visiting other resorts, fishing in the lake, enjoying the beach, dining at Hoop and Trail's End then 100-400 and 700 would be ideal. What does that leave? 500, 1200, 1800-1900, and 2000... what are they, chopped liver?! Not at all! 500 is my favorite all-access loop, a nice combination of convenience to both the marina and the Meadow recreation area. 1200 is close to the pool without being on top of it, and it has easy access to two bus routes. 1800, 1900 and 2000 are all pretty isolated, which means quiet. All this to say, there is no such thing as a bad loop, but there are certainly different benefits to different loops.