What impresses me most, besides the run itself, is that you remember so many details. Were you recording as you ran? My favourite line: "Absolutely no distraction from any thoughts of the outside world, just one single task upon which all attention is focused." It's worth doing for that reason alone.
The happiness experts say you should buy experiences and not material goods. I can't arrange to have experiences like this often, so in order to get my money's worth an important part of my task is to form memories of the day. It pains me to think how many of my days leave not the slightest trace in my memory, though I am thankful that at least I don't have many painful memories. A GPS record of my progress is helpful, and I also take down some notes at the end to help jog my memory when I eventually start putting together a report like this. The job is made easier by my hope of making it into a good story rather than an accurate one. "Just one single task" is almost a fantasy. Getting things done is satisfying, but to me it's an impossible challenge to be organized and motivated enough stay ahead of life's routine demands. Working on any one task necessarily means ignoring others. So on top of everything else one senses the additional duty to seek balance and peace. You can't win! Having just one goal for twelve hours straight feels amazingly simple and liberating.
I have considered taking photos or recording an E-Vox along the way, but it seems too much a distraction from the goal of conveying oneself from the start to the finish as expeditiously as possible. That long dialog was fairly approximate, meant mainly to illustrate the way that socializing can help break up the monotony of a fairly individualist activity. I did want to get my use of the line "Is it because of the metric system?" on the record, as dropping unappreciated "Pulp Fiction" quotes into conversation is a personal indulgence.
Key West in June would be ideal. Training in heat makes performing in temperate weather seem easy; it's the secret of the futbolistas who practice in the polluted atmosphere and high elevation of Mexico City, then when they play away games it's like they're breathing pure oxygen. The good news is that your training is already about 90% complete, now that you have adopted a positive attitude to the idea. If I have learned anything about endurance sports, and probably any kind of physical performance, it is that once you get beyond amateur level it becomes largely a mental game. Good knees are helpful too, so your cycling habit will be to your advantage.