It sounds like your boat was built around 1965.
While there can be much to love about the old fibreglass boats taking one on a long voyage through some of the toughest seas on the planet is going to test every part of it.
At the very least I strongly suggest getting an experienced surveyor
to look at your boat, preferably before you start any major upgrades.
You could find that your boat may sell for enough that when the money
is added to upgrade, modification and voyage costs you have enough to buy a respectable cruising boat in Southern California
or many of the other cruising areas around the world, with some left over for petrol to drive your car south.