I started upping my mileage on the bike earlier this year. I was surprised at how quickly I adjusted to longer rides, and how soon I was doing regular 100 milers. The 2 biggest issues I encountered were 'the bonk', and mechanicals, in the middle of nowhere, and miles from home, or a train station.I still hit the bonk occasionally, regardless of loading previous to the ride, and planning sustanance stops en route, it just means I tend to give myself an extra 30 minutes - 1 hour window, to allow me to slow down if I think I'm getting close to empty. I tend to carry more emergency repair kit than I used to as well now, but I've got small gas inflators rather than bulky pumps, and I always carry spare links for my chain now, as well as the usual couple of tubes. I don't worry about the big mechanicals too much, as I've really only had one show stopper, in several years riding (a collapsed wheel). I walked the bike to the nearest inhabited place, asked the local pub landlord if I could tie the bike up at his pub overnight, got a taxi to the nearest train station, then went back the following day, with a new wheel, did the repair and rode home. It wasn't as bad as I'd imagined in the end.
