If the coating on it now is checked, I'd sand and scrape to remove anything loose and then hit it with a bonding primer like Zinsser Peelstop or XIM Peelbond just to make sure it's all glued down tight. Then topcoat with whichever paint you desire.

 

If it's really gelcoat, and it's crazed as you say, then a light sanding and recoating won't cover the crazing. You need to either fill the crazing with some filler, or sand down the gelcoat to a smooth finish before repainting.