I'd take your time working up to the Krispy Kreme trip. 58 miles both ways is a haul.

Not sure how far your commute is, but if you're collapsing on the floor for 10 minutes after it, you're going to need more conditioning before knocking out 120 miles in a day. I rode for a solid six months before I attempted my first century and felt like death after it. I bonked hard and took about an hour to recover once I got back home.