Barry - I don’t have responses to all your questions, but…
Breakaway sells wetsuits. On Chestnut, around 20th… I assume you can try them on first, but you could call.
For the open water swimming - well, a friend and I did do a few practice swims in the schuykill. It was fun, a bit silly. We stayed by the bank and swam downstream. If I do it again I’d probably go upstream too, but not across the river.
There are certainly group rides around, although I don’t do many of them. Just personal preference. The freedom valley ride is coming up, though, which the greater philadelphia bicycle coalition runs; could be a good networking opportunity.
You may want to check out Suburban Cyclists Unlimited (www.scu.org) for information on group rides in Montgomery County. The training staff at Breakaway Bikes in Philly may also be knowledgeable about training groups. A decent local shop in your area may also have a line on training groups - several run occasional triathlon clinics. The other option is to just get on the Valley Forge trail and try to meet people. The ones with aerobars are probably the triathletes.