I was taken aback when Eric opened the door of his tiny plane, with two seats one behind the other, and he told me to sit in front. Assuming I misheard him or he was on some mind-altering drug (in which case, perhaps I ought not to be flying with him at all) I took the back seat. "No, climb in the front. You're going to fly."

What? I felt a nervous, panicky tingle run down my spine. He reassured me that the back seat had controls too, so he'd take care of the takeoff and landing and I could do the rest. I felt like quite the official pilot when he handed me a headset and explained that we'd have to talk to each other through those in order to hear above the engine noise. He had me prime the fuel pump and start the ignition, then started taxiing out onto the short asphalt runway. Once we were in the air, soaring over the Estrella Mountains, he handed the controls over to me.

I'd warned him ahead of time that I tend to get motion sickness on tiny planes like this, but it was a clear quiet day so he said we would not run into any turbulence. That was true. We'd had a perfectly smooth ride thus far, until I took over. Treating the controls like a video game joystick, I had the plane lurching and dipping uncomfortably, making my stomach drop and my breakfast threaten to rise. That was good motivation to learn to maneuver more smoothly.

He explained that the joystick is pretty sensitive and requires only subtle movements. I'd also have to use the rudders, two foot pedals, to keep the plane level as I turned—conveniently there was a level, just like the carpenter's tool, right on the dashboard. That helped, but a couple times I tried to turn right by holding the joystick to the right, and when I let go we'd be continue going in a circle. It turned out you have to just move the joystick once to the right, and then the plane will keep going to the right until you negate that movement.

It was tricky business, the whole flying a plane thing. I never got to the point of 100% confidence that I could guide it in the direction I wanted it to go. I'd pick a ridgeline and try to navigate along it, and sometimes that would work but at other times I'd have to pretend that I'd meant to go some other direction entirely. But it didn't matter in the grand scheme of things because I got a great preview of my ride for the day, which would take me through the Sonoran Desert and past the Estrella and Maricopa Mountains, a huge recycling plant with piles of tires around it, and the town of Mobile, a town with a decent sized dot on the map but which contained nothing but a police car, a fire truck, and an elementary school ("I can't imagine where they get all the kids from," wondered Eric).

We also saw a few things that wouldn't be visible from my ride, such as the old Butterfield Stagecoach road that once took passengers from Phoenix to Yuma. Eric told me that this leg of the journey was done at night, which is why the mountains were named the Estrellas, which is Spanish for "star."

We were having a good time tooling around until we discovered it was a few minutes before 11:00, which was when Eric was supposed to be at work. So he took back the controls, dipped us down over the mountains close enough to see the saguaros waving up at us, then made a beeline back to the glider port.

It was a pretty awesome feeling to have already had more than my fill of excitement by 11:00am. I rode off feeling like the luckiest girl in the world. How often does one get to go skeet shooting, sleep in a glider port bunkhouse, and fly a plane within the same 24 hour period?

The ride down a perfectly flat desert road extended my good mood too. With my journey drawing to a close I was determined to enjoy the wide open spaces, stark rugged scenery, and empty railyards while I still could, so at lunchtime I had a picnic right on the railroad tracks like a true hobo. The side of one train car had a vise sticking out of it. I like vises. I racked my brain to see if I had anything that need to be clamped, and didn't, but I did use the handle a bar to grab onto while stretching out my achy back.

One of the best parts of this journey has been the sense of truly being in the world. My life in Boston feels very abstracted in some ways. I work in front of a computer and deal with information: pixels, colors, code, text. I then go to a gym and perform physical tasks that accomplish nothing, running in place and repeatedly lifting heavy objects. There is something profoundly satisfying about doing real things with tangible results: transporting myself to new places under my own power, finding shelter, procuring supplies, locating roads, fixing flat tires and dog-savaged footwear, jumping over gates, feeding horses. The less pleasant experiences—shivering in the cold, fighting the wind, stepping on a goathead burr—contribute to this satisfaction just as much, if not more. They remind you that you are alive.

Such were the things I contemplated, alone with my thoughts on a peaceful, gorgeous, easy ride through the Sonoran Desert. The mountains, North Maricopas on my right and the South Maricopas on my left, provided a stunning backdrop to expanses of desert scrub and the occasional cluster of saguaros. The miles flew by and eventually I rolled into Gila Bend just as my empty stomach had started to growl. I estimated that I'd have enough time to eat another lunch and still get in another 20 or miles or so afterward.

While I ate my quesadilla I pulled out my road map to scope out a camping spot that would put me within a bikeable distance to Mark and Faye's place outside Yuma., and in doing so discovered they were just a shade over 100 miles away. I knew I-8 would be flat most of the way, and a quick check of the weather forecast indicated I could expect another sunny day with negligible wind. And I was highly motivated by pictures they'd sent of their luxurious-looking "biker bungalow" with a hot tub nearby. All these factors added up the perfect opportunity to try for my first century.

I called Mark and he confirmed this information—in fact, he and Faye do century rides from time to time by riding to Gila Bend. He said I was welcome to come in the next day if I could make it and gave me directions which included, ominously, going "over the mountain." At least he did not say "mountains," plural.

It was exciting to discover that by 3:30 in the afternoon my work was done for the day. I celebrated by checking into a motel, my last motel of the journey if all goes according to plan, and taking a nice long nap.