"Branson plans to be doing _inter-continental_ suborbital passenger flights within 3 years??? "
No, but flying passengers few hundred miles, maybe. But that's ahead of paper studies for 3 years. I think that Branson is on a path that will get to a New York to Tokyo route in 3 hours [half the time]. The SpaceshipTwo won't do this- except perhaps as a stunt and maybe it will take longer 6 hours.

"That's a heck of a lot more ambitious than anything I'd heard about. In terms of the engineering alone there's a huge difference between the delta-V required to zoom up to 100km and come right back down in the same spot (even the V-2 could do better than that) vs completing half an orbit. Not to mention a far more stressful thermal environment on the way down, since your velocity is so much higher. "

But they wanted to stay in same location. Take SpaceshipOne, fly the mothership towards to location you going to then launch with idea of getting as much distance as you can. We haven't seen this yet. SpaceshipTwo will be improved version, SpaceshipThree might get to New York to Tokyo in 3 hours with passengers taking two or three suborbital hops.

"Not to mention that I don't think the Virgin-Rutan effort is meant to provide reliable, timely passenger service. I don't think you'll be able to call them up and say, "I have an important meeting tomorrow morning, can I get a seat on this afternoon's rocket?".

Maybe in ten years. Depends upon how aggressive [how much finanical risks he and others will take] and how successful the beginning is. More likely 20 years. But once you around this point, suborbital travel will be the preferred way to get from LA to New York, just as airline travel was preferred over taking a train 50 years ago. The technology will be difficult, but govermental laws will be the bigger problem.

"Adventure tourism and time-sensitive business travel are very different markets, even if the ticket prices were the same."

Car or plane they all start as "adventure tourism". In next 5 years suborbital travel will be horseback rather than coach.