Is what you did feasible to do remotely? That is, using email/phone/video chat only, or are in-person meetings crucial at this stage?
With cofounders, it's very difficult to be remote, because you have to make very complex decisions, often under a lot of pressure. My cofounder was in SF and I was in Silicon Valley and that commute was already killer; if we were in different metro areas I doubt it would've worked. Being able to get together at one of our apartments to hash out some product design or go over notes from customer interviews was critical.
For customer interviews - they can be (and often have to be, if your target customer base is spread out) remote. Most of ours were over the phone, with a few over email/Skype and a few meetings in person whenever they were local. You get more information out of an in-person meeting, though, since you can gauge their body language and emotional state. Indeed, I think we would've learned the problems in our idea faster had we done more in-person interviews: we had the contradictory data where the students we interviewed in person often seemed lukewarm or disinterested while the ones we interviewed remotely were very enthusiastic.
There's been a lot of criticism of the tech startup industry for focusing on problems only young people in SF/NYC have, or that only engineers have, but actually going deep in an area we're not already familiar with seems logistically and financially impractical for most people.
It was a huge pain and expense for us to have to fly to New England to launch & get real user feedback. (Our target users were students at liberal arts colleges, because we believed they needed the product more than CS majors at top Bay Area universities. Even so, we did some user-testing at Berkeley and Stanford, but discounted the results because "they weren't our target market".) It was less expensive than continuing to work on the product for another month would've been.
There is a reason why Facebook started at Harvard, SnapChat is in LA, and the AirBnB founders were shuttling to NYC every week during YC. They didn't have to stay there, but they made a big effort to be close to their early customers. Now imagine what someone who was a native of that area could accomplish if they went after local customers with the same energy.
While there is obviously value in in-person interactions, I would strongly recommend balancing it with some online interactions as well. People tend to be MUCH more honest about your idea if they know there is distance and a level of anonymity between you and them (see also: Show HN :-)
(Source: Worked in market research industry doing customer interviews and qualitative research for almost 15 years)
You can compensate for this somewhat by gauging emotional response - someone whose eyes shoot open while exclaiming "You can do that?!" and then tracking you down when you walk away is probably a much better prospect than someone who says "Oh, sure, I'd use that" in a level tone of voice. But for my latest venture, I've been using a combination of AdWords and going to meetups to validate the idea: each of them tells something that the other doesn't.