I don't know about the grandfathered thing. The charge to connect your home to Comcast, even if you have never had Comcast at the residence, is not too bad. Something like $29.
I do know Comcast offers a special deal to their Florida customers called a seasonal convenience plan. You can put your services on hold for a minimum monthly price. That way you don't have to pay the regular monthly fee when you aren't there and you don't have to connect and disconnect every time you leave or come back to your Florida home.
Page 2 of this brochure explains the plan.
http://www.comcastflorida.com/swflor...on%20Rates.pdf