In theory, Downtown Disney busses run every 15 minutes, and from the Yacht Club, it should be no longer than 15 mins to the Marketplace. Of the many times I've driven out of Downtown, I've never really seen any major problems with busses being late and whatnot... Of course, I end up hearing about it when I drive other routes. Something fishy always goes on with DTD busses. I think I'm going to start calling them Bermuda Triangle busses. Whenever I work for other hubs, I always get people yelling at me about the DTD bus. (On a side note... please don't yell at the Magic Kingdom driver... they have nothing to do with DTD...)
As for dispatching... When CBR is open, during peak times, we'll run CBR/DTD busses so close that there will be at least 1-2 DTD busses within CBR at any given moment. All-Stars sometimes gets busses dispatched every 6 minutes... they're practically on top of each other.
After seeing all the dispatching that goes on with DTD... I don't know what's going on to cause the delays that people are always talking about. Not saying they don't exist, but, when you watch Field 5 dispatch all these busses, it makes you kinda wonder what happens?
*steps down from soapbox and looks above*
Okay, so maybe I didn't answer your question, and just ranted instead... LOL... but suffice to say, wait for the DTD bus at the Yacht Club. If for some reason you're starting to cut it close and the DTD bus hasn't arrived, they have cabs just a few feet away.