Running SEO Company ranked high for another country...

This is a deal which has come up for me very recently, and really need your guys honest opinions and whether this will actually work. OK, I was on a website auction site (yeah, that one) and I won an auction for a site which was ranked highly for a large city in the US. First page for keywords, [city] seo, seo [city], affordable seo [city],[abbreviated city] seo , etc,etc.
So it checks out for this, and the seller seems legit too, he has sites in other large cities and he can maintain this ranking personally, as well as show me what to do with regards to SEO side - whether I do it myself or outsource.

What my question is though, is this feasible for me? I am from the UK, so would not be able to go out there to get the clients. It is apparently getting about 10 enquiries every week through google organic traffic so as long as that does happen, I just have to close them effectively.
Ideally don't want to be pumping more money into this, so its essential that this site will work as is.
If any of the SEO guys here want more details pm me, as don't want to go into specifics here on url or anything- would be very much appreciated to get some of your thoughts.