I recommend Don Casey's
Complete Illustrated Sailboat Maintenance Manual
Boatowner's Mechanical & Electrical Manual
I Googled the Windrose 18....nice little boat ya got there! The cushions, you're gonna have to measure and have them made unless you get extremely lucky and find someone who has some and is willing to sell. Not likely....just look at pictures online of others and get an idea of how many cushions and the layout, then measure up and have them made.
Does you boat not have any electrical at all? In one picture I saw an electrical panel...I would assume she's got lights? (nav and interior) Or is it all stripped out and ya gotta start from scratch?
In either case....2 most important things....use a marine
deep cycle battery, and all wiring must be marine grade pre-tinned. Other than that, try to use LED's wherever possible, a good charger for shore power
, and an outlet or two for 12v stuff.