In all honesty - I'm not even sure how much time you have to put in to finish a marathon. Most people could "finish" (as long as they're OK walking part/most) but finishing with any kind of speed is an entirely different deal.
I'd love to qualify for Boston sometime. I've run Ogden a couple of times, and it's a fun race. But I'd love to run one of those big city races that has thousands of people running. Around 6K versus around 30K.