For cell coverage, don't expect anything as good as the lower 48. Cell tower installations are few and far between, but most communities have coverage. The local companies are ACS and GCI. I think ACS has better coverage statewide in maritime communities. Both offer high-speed data. AT&T is a joke up here, but it would probably work in Juneau and Ketchikan. I'm sure it roams to GCI GSM when needed. ACS is a CDMA system.
Petersburg had the best moorage rates. Juneau and Ketchikan had several choices. We keep the boat in the water
all year long, but have to deal with large amounts of snow further north. SE doesn't have that problem, but the rain will test every water intrusion point on your vessel.
You will probably want a boatwatch type person to check the lines and address any physical issues while you're away, or at a minimum, arrange a contact person. I have put my own monitoring system in and watch shore AC, motion, and high water. You will also find yourself watching the weather
Great cruising around SE, and you should have no problem finding good salmon streams. Check out this site...
ADFG Fish Resource Monitor
It has the keys to the kingdom of fishing Alaskan fresh waters...Have fun.