Heaviest load: Hm. I was on a nine-day backpacking trip back in 1985 with a Sierra Club group. We had some sort of weight limit, but I don't remember now what it was. I do know that I managed to meet it by keeping my camera equipment (35 mm SLR; 28mm, 50mm close-up, 70-150mm zoom, and 300mm lenses; tripod) off the scale.
Longest single dayhike: Distance-wise, 22.9 miles, I think it was, for The Bonds from Lincoln Woods. Time-wise, maybe Seymour in the Adirondacks. I know that was 12 hours 20 minutes. There were probably ones that took even longer, but that one stands out. On my bicycle, I did one century, in the Northeast Kingdom, back in 1982.
Quickest climb: Probably my climb of Tecumseh, one hour five minutes. I had already climbed Starr King and Waumbek earlier in the day, and I didn't even start that hike until 11:30 a.m. I started the Tecumseh hike at 5:20 p.m. on September 21, 2000, so I made it to the summit just before sunset. Descended the ski trail in the dark, reaching my car about eight o'clock. Slide Mountain was just over an hour too, I think, with my then-10-year-old son along.
Tallest mountain: Mount Washington is the tallest mountaintop I've summited on foot. Maybe Slate Peak in Washington is the highest I've reached by car. The highest point I've reached on foot was Red Peak Pass in Yosemite National Park, 11,300 feet in elevation. I hiked the Pacific Crest Trail from Harts Pass to Rainy Pass back in 1984; it looks (from my notes) like our high point was Tatie Peak, 7000 feet high. I don't remember hitting any summits on that trip, though, so that must have been a shoulder.
Windiest summit: Probably Wright, October 7, 1998. Susan and I were afraid to stand up on the summit. Cardigan was memorably windy, too. I know my son (maybe about five, then) was terrified. His hat blew off his head and sailed down the mountain, luckily landing at the feet of a man looking at the scenery. He returned it to us. I can still hear Cam's wail of "my hat!".