If you built the boat yourself, I can really understand how you'd want to keep her, especially after so much effort.
A lot can happen in 3-4 years. If you can safely store it on a trailer on someone's property, it could possibly be done cheaply, but you will find lots of stuff to fix when you re-commission her. It just might be easier in the long run on you to sell her, let someone new enjoy the use of her, and buy a new boat when you return to being close to the water. In even a year, the accumulated growth on the bottom will be astounding: I can't even imagine 4 yrs.! A homemade plywood
kit boat, I would not leave her in the water, if somebody else built her. You have to keep the water on the outside, or you lose all.