That's a LONG commute. I would do a partial commute. Before settling on a folder, though, check to see what the local transit services offer with respect to bike accommodations. In Fort Worth, virtually all buses have a rack on the front for bicycles:



...and they allow bikes on commuter trains as well (although a cyclist may end up standing there with his bike)



Another option is to drive to work with your bike, then ride home. The next morning, ride back in, then drive home. That way you're only doing the 31 miles once each day, which is conceivably do-able, but is still may be a stretch for you in the beginning. It may take you 2-3 hours to ride the 31 miles depending on traffic, hills, etc.