I'm taking a shot at posting here even though I'm a mini-Clyde (210 lbs+). Hadn't been on a bicycle for almost 20 years and am trying to get back into it at age 62. Bought new bicycles (Wife and I) about 4 months ago and 997 miles to date. Today I rode 41 miles with about 1800 ft. of climb. Didn't push and averaged 14 mph. Is this fast enough to find a group riding out of a bicycle shop or local club to ride with once a week? I could have perhaps average 15 if I'd pushed it, but I wonder if groups typically going 40-50 miles aren't going somewhat faster.
I've been very pleased with my Giant OCR1 and particularly not having had any flats! I can generally ride 3-4 times on the weekdays for about 15 miles on my lunch hour, all this to be able to do a century in the sping. I think 2000 miles or so will probably give me enough of a base, but I sure wouldn't mind taking the longer rides with a group. My wife and I do ride together, but she doesn't like hills.