The original message was from 6 months ago so I suppose the vacationer has already come and gone. I have AT&T for cellular and I have noticed a few dead spots while looking at property in the Meredith area in the late summer; including a lack of coverage on Meredith Neck.
AT&T has a huge dead zone in the area to the south of the lake; from Alton down to Epsom there is basically no AT&T cellular coverage.
You can look more closely here:
http://www.wireless.att.com/coverageviewer/