If you leave it in the water, I'd want at least two automatic bilge pumps run from separate batteries to handle any problems with leaks. It's doubtful that you'd have a catastrophic leak but small leaks are quite common and can sink a boat if not caught soon enough. You will also have to have a charging set up for the batteries. A shoreside powered charger is probably the most common but smallish solar panels might not be a bad thing just to be sure. I'd also wire in a cycle count meter into the bilge pump circuit so you can see how often the bilge pump cycles. A cheap engine hour meter would work and assume you could buy a purpose made meter.

Hire someone or get a reliable friend to check on the boat at regular intervals. Might even want to pay them to wash down the boat monthly so it doesn't look abandoned. During the off season, very few people are on the docks and a slowly sinking boat might not be noticed until only the dock lines are holding it up. In the 4 years I commuted to the boat, had to alert the marina management twice to power boats that were riding very low in the water and a sailboat whose mooring lines had chafed/ were getting ready to chafe through. Kind of amazing considering how little I was at the marina.

Storing it on the hard is safest though you'll want a secure yard to deter theft and/or vandalism.

I used to commute a couple thousand miles to my boat at about 3 month intervals. One time getting back to the boat, noticed the bilge pump seemed to be cycling often. Turned out the bilge pump was back syphoning. Fortunately it hadn't been going on long as the batteries were down quite a bit but not totally flat. Even more fortunate, the bilge pump float switch took a southern vacation while I was trying to figure out where the water was coming in. Never did figure out why the syphoning suddenly started 2 years into my ownership. An anti-syphon valve in the bilge pump discharge hose cured the problem. Added Solar panels to keep the batteries charged and a second bilge pump gave me insurance against a switch or pump failure.