On the original poster's topic, I agree that a county project would achieve greater results within the powers of that county (provided that the residents don't get so alarmed by the prospect of a tripled population literally "taking over" the county that they enact ordinances against new movers). But since the county powers are so limited, and have no Constitutional claim to sovereignty (whether or not you like it, some of the people who would help bring about a more free society will still subscribe to the idea of constitutionally-limited republics rather than anarchy and will be more likely to support the cause if the seceding entity has a legal claim to that right), it seems unlikely to achieve much.
You have a valid point about the power of the Federal govt overwhelming whatever we do at the state level, assuming things continue along the current track (but we don't have enough libertarians to rein in the Federal govt, and I don't know how much the soon-to-be conservative and Tea-Party partial takeover will do for even economic freedom, longterm), so we are doing all we can with this project.
Realistically, what could a free county do if the parent state refused to let it go? And how is a county of 10k going to support a sudden tripling of the population? There are some issues with your idea too.
You know what, the FCP is not mutually exclusive with the FSP.
That is - there is nothing preventing a large percentage of the FSP signers from moving to the same NH county, provided that's what they want to do, so I don't see this idea as a reason NOT to do the FSP. Why don't you start a NH FCP project and see how many signers you get? There is only a conflict if you insist on doing it in another state. Even then, you're going to have the same major problem that the FSP has had getting movers, which is a large percentage of liberty-loving people not wanting to or able to leave the state they live in now.
If the FCP project works, great. However, if you choose to do it outside of NH, you're not going to get many people from this forum to participate, as most of us are already committed to the FSP (and in my case, the Next 1000 and a move date as well).
If your FCP is not successful, then you haven't made things any better by not doing the FSP. By the way, I wasn't trying to suggest everyone has to do political activism, but there is a much-higher concentration of pro-liberty civil disobedience, agorism, and media there in NH too (You can certainly try these things other places, many people are, but I don't see them being nearly as effective as when done in greater concentrations).
I'm not trying to convince you that you have to do a Free anything project, certainly lots of people in other states are doing a lot to raise awareness - the Austrian economists and plenty of libertarian media out there for example. As far as I can see, though, the FSP is the only project with a realistic chance of showing that these ideas actually work in the real world
The other free state projects don't have enough people or are tackling states that are geographically too large to even gather the activists together - I mean WY, ID, MT are all HUGE states. Some of those low-population counties you talk about are pretty big, too. Even there you'd probably have to concentrate on the population centers of the county, and then you might as well make it a handful of free town projects. This is being done in NH already, so where's the beef, unless you just think NH is the wrong state?
Besides, you're assuming the 20,000 movers won't be able to influence a large number of the 1.3 million natives to join their cause. I've always understood that one of the reasons govts grow is because the people wanting smaller govt have less incentive to lobby the govt, and spend less time in the political process than the people looking for a handout. In NH, we can change that! With organizations like the NH Liberty Alliance, the NH Taxpayers Coaltion, etc, and a more accountable govt structure, the apathy / despair the common people have in other states is already much less in NH, even with less than 1000 movers!