Hey Broods! Glad someone else is posting in this thread for a change!
I just finished IM Arizona last Sunday. There is NOTHING like finishing an Ironman. Nothing. It is pure elation.
What type of tri are you considering? There are 4 main distances:
Sprint: 400-750M swim, 10-12.5 mi bike, 5K run. Sometimes these are unusual distances but the usual distance in 750M/12mi/5K.
Olympic: 1500M swim, 40K bike, 10K run
Half-Ironman (70.3): 1.2 mi swim, 56 mi bike, 13.1 mi run
Ironman (140.6): 2.4 mi swim, 112 mi bike, 26.2 mi run
Clearly, it's best to start with a sprint distance. The distance and training are the most manageable, obviously.
It sounds like you have a great running base to build on in addition to a good aerobic fitness platform in which to build...so that's a great place to start from.
Re equipment..triathletes LOVE their kit/gadgets,etc. A hybrid bike will be fine to start...there are many, many road bikes, MTB, hybrids in most local races. As you get into the HIM distance and beyond, you'll want a triathlon bike unless the course is hilly/technical..climbing is harder on a tri bike than a road bike. Riding in aero position on a tri bike will make you faster and more comfortable (after you get used to it) in addition to preserving your leg muscles a bit for the run. To begin competition you'll need swim goggles, a bike/helmet/bike shoes and a pair of running shoes. That's it. As you get more into the sport there will be a ton of stuff you'll want to get...aero helmets, racing tri kits (so you don't have to change clothes in transition), racing bike wheels, a tri bike, power meters, etc, etc. It gets expensive like most adult hobbies...but it's so worth it.
Swimming: I was not a trained swimmer so this was the biggest challenge for me. I took a Master's class at the Y and went from needing a swim snorkel to go 25M to swimming 1,000M in just a few lessons. After that, a swim coach can really help refine your technique to get you faster and more comfortable in the water. Training in open water is a must. There are skills you'll need in OW like sighting (staying straight, seeing the turn buoys, etc.) that can't be reliably practiced in a pool. I do 90% of my in-season training in OW.
Once you decide on a bike...please get a professional bike fit no matter what type of bike you employ. Clipping on aero bars to a hybrid or a road bike is a common quick fix that can lead to miserable biking experiences. An indoor trainer is really helpful especially in the northeast so you can train when the wether is an issue. Luckily, there are a ton of used trainers available for sale so you can pick one up cheap.
I'm in VA so don't know much about the NY races but Ironman Lake Placid is supposed to be an amazing venue.
Hope that's enough to get you started! Shoot me any q's! Glad you're getting into the sport...it's addicting! It's also very kid-friendly so you can compete as a family. At IM AZ, they had a couple of races for the kids and the pride in which they wore their finisher T-shirts was cool to see!