I'm sure there is a lot more that you could do but what you are doing sounds
like plenty. One suggestion, don't cover it up wet, if necessary leave it out
overnight uncovered and cover it up the next day after the sun dries it out.
Trapped moisture is what kills things on boats. Better is a car port type of
deal to keep the sun and weather off it. Mine is a silver tarp on an electric
conduit frame over my lift.