I hover around 250 or so (actually a tad higher right now) and have been riding just over a year. I've probably got in something like 2500 to 3000 total miles (I didn't have a cycle computer til after Christmas this year, and it's got about 1500 showing on it).
The furthest I've ever ridden is 73. That was last weekend. It's hilly here in the Ozarks. Average speed was 12.1. Before that my longest was 55 (birthday ride your age deal) in April, on my first bike, the Navigator. I'm signed up for the Queen City Century next weekend.
Routinely ride 30 to 35 miles mixed in with a 20 or so here and there. I ride at least three nights a week, up to six if time permits. I don't have much in the way of speed, but my stamina has seen a lot of improvement over the last year. I've lost about 30 pounds from riding, no major changes in diet.
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It's all downhill from here. Except the parts that are uphill.