If a marathon feels a little bit short for you, then the obvious next distance is a 50K race (~31 miles). And it just turns out that there’s a 50K race coming up in about a month: the Sasquatch 50K & Relay. This race bills itself as a “classic beginner 50K” but follows that with “(the race director’s attempt at humor).” I’m no expert on ultra-marathons, but this one looks fairly challenging. It’s almost entirely…