Like many memorable adventures, this one had an inauspicious start: It rained from dawn to dusk.

About 15 minutes in, still in Chicago, I made my first stop at Lulu’s Hot Dogs. When I mentioned my plans to Don Grieco, one of the owners, he told me about a similar trip he’d taken to drop his daughter off at college in Flagstaff, Ariz. — “mostly on 66,” he said. He wished me luck.

Twenty minutes later, the rain picked up and I ducked inside Henry’s Drive-In. “Big Girls Don’t Cry” was playing on the radio when I settled into a booth.

At a table across from me were Karin and Ewa, two friends from Europe who had also begun their westward trip in the rain. A couple of days later, I’d run into them again in St. Louis — the first of several traveler reunions, as I came to think of them, that lent my solo trip a sense of shared experience.

I can’t get far without telling you about the giants.

Route 66 is lined with large, fiberglass sculptures affectionately referred to as “Muffler Men.” Mostly built in the ’60s and ’70s as roadside advertising displays (some for muffler shops), the hollow sculptures were repurposed over the years — including one, called the Gemini Giant, that stood for several decades outside the Launching Pad, a defunct diner in Wilmington, Ill., before being moved to a nearby park.

Gazing up at the behemoth, I turned to see a man dressed head-to-toe in black riding gear. It was John Power, from Ireland, who had flown to Chicago, rented a Harley and begun his own Route 66 trip earlier that day.

Shortly afterward, menacing storm clouds materialized, and the light rain gave way to a torrential downpour. Tornadoes sprouted on the Illinois plains. I pulled into a gas station, parked my bike under the canopy and huddled in the snack aisle along with a small group of stranded travelers.

It was dark when I made it to my hotel, my boots so thoroughly soaked that the soles were falling off. I’d covered 100 miles — less than half of what I’d planned.