Angus, I live up in that frozen wasteland called Canada & my boat is on the opposite end of the continent on the gulf side of FLA. Like you I stressed about being so far away, our boat sits for months unattended. I do the same as MV Traveler, I close every seacock on the boat and turn off every breaker except the battery chargers. Except for being robbed twice everything has been fine. I do now have an alarm & camera system that allows me to look in on it from time to time. Best of all, I also found a member of the forum here who only lives a few blocks away & keeps a close eye on it for me, god bless him. I still stress about it though as one of my recent post's regarding the current flooding in Fla will attest, but it's a manageable and mostly unwarranted stress now.
Do what you can and Relax, beautiful ship by the way!