Cabin lights and radio should not run down two good batteries, so I must ask what size are the batteries and how old are they?
I know you get got the boat so you may not know the age of them. Sounds like they took enough charge to recover I guess in a week or so you will find out if they hold a charge or you could have them load tested.
1997 2400 SCR
5.7 Vortec / Bravo 2