I have a 25, which had a lot of hiarline cracks- DO get "this Old Boat" like the man says- GREAT book. It will tell you to scratch or moto-tool the cracks out- make them bigger , clean with acetone, and fill in with gelcoat- you might have to match the color, carefully.
Buy all your solvents and such in gallons- you will be going through those I did a LOT of cracks on mine, but they are GONE now! Worth the job, and it's not hard.
Your plugs on top may be "solid" . What I have seen about 25s at least is that they ran the wires before putting the top on, and glued the whole mess in. I had to replace my mast connections last fall, and wound up just drilling a hole next to the old one, putting in a flush mount receptacle on the deck and running a short surface wire along the head bulkhead to the port side, heading aft on top of the headliner. NOW would be a good time to think about upgrading the number of connections - I went from 2 to 4. If you have trouble finding multi-plugs and connectors, try RV/trailer places- they sell some rugged stuff, and 4/5/6/ strand wire. I used 4000 to fill the hole and seal the deck.