Did not see this suggested; to help the OP get better cell service in their 2nd home, they can take advantage of a Femtocell. Basically, it's a mini cell tower that plugs into your broadband connection. The only minus is, one would need to be purchased per cell provider. Links:

http://en.wikipedia.org/wiki/Femtocell
http://www.att.com/shop/wireless/dev...gmicrocell.jsp