Location: Machens, Mo.
Distance: 238 miles
Best Suited For: Road or touring bikes
Website: bikekatytrail.com

It's the longest rail-trail project in America, and it nearly spans the state of Missouri east to west. With smooth crushed limestone and flat terrain from end to end, bring whatever bike you're comfortable on, and a lot of time, as you're probably not going to hammer this out in a weekend. Grab a map too, as you'll want to plan out your food stops.