". Replace thru-hulls and seacocks (all seacocks are seized)"
If the seacocks are proper tapered bronze , the can easily be made perfect again.
When on land remove the nut holding the taper in and tap the shaft with a piece of wood and a hammer , to not damage the threads.
A bit of fine valve grinding compound as you hold the tpered plug in place and it should be as good as bew.
Some folks will replace the 1/8 in winter drain plugs with SS outboard zerk fittings and give the unit a hit with grease before exercising it.
Thru hulls only need replacing if pink from electrolosis.
Store all fuel or oil filters and rubber hoses and belts in an air tight bag.