All true a few years ago, but Lyme is spreading.
LD_2011_dot_map_550px.jpg
I suspect it's still true that the incidence (cases/100,000 people) is highest in coastal Conn, eastern Mass, and coastal NH, but I may be wrong.
If you look at this link to maps for 2001-2011 and click on year on the left, you can see how it's spreading:
http://www.cdc.gov/lyme/stats/maps/interactiveMaps.html
In 2001, Lyme was very rare in VT or in the NH mountains. It's still rare in the far north of VT and NH, and most of ME. But, as of 2011, VT, NH, and ME have a higher incidence than Conn.
It looks like the places in the northeast to hike to avoid Lyme are the Adirondacks and Maine well away from the coast.
These maps show cases by county, so don't read too much geographic detail into it. The dots are placed randomly within the county of residence.