This topic has come up several times since we started living on Cow Island 13 years ago. Some links to related threads below.
The concept of extra "lugging" always puzzles me as the
only added effort is the transfer of groceries from your car to your boat. Most boat access places allow you to park pretty close to your boat (20' away at Harilla Landing). You will need to secure access to mainland either by owning or renting a dock or rack somewhere (i.e. for Cow Island: Harilla Landing Yacht Club; Pier 19; Melvin Village Marina; Pick Point; Quayside Yacht Club) Trash removal is not a problem if your mainland facility has dumpsters (most do). As far as services, there are several handyman services available throughout the Lake that will be happy to help you out with whatever you need done. And the minor added cost of having the service done on an island is likely far less than the added cost of taxes on the mainland.
Most of the islands have power and phone. These days it's almost a must to have Internet access to keep in touch and get news and most important, weather. We use DSL but some use wireless broadband. Check availability where you plan to buy.
I wouldn't trade island living for anything. The camaraderie of fellow islanders is great. Plenty of help from you neighbors and frequent get-togethers to share the good times.
http://www.winnipesaukee.com/forums/...ad.php?t=17325
http://www.winnipesaukee.com/forums/showthread.php?t=17321
http://www.winnipesaukee.com/forums/...ad.php?t=17212
http://www.winnipesaukee.com/forums/...ead.php?t=3359
Good luck.