I use old pieces of PVC and tennis balls to hold my cover up. The stripes denote where they go, one stripe is for the bow four stripe is in the stern. Cost was exactly zero.
I helped a friend dump his 25' boat here. I don't remember what it cost and they actually helped get the boat off of the trailer.
https://oclandfills.com/landfills/prima-deshecha-landfill
That's what I wished I would have done. Check with a couple of mechanics to get their opinion on your motor. It's easy to glance at the pisser once in a while to confirm the water pump is working, that's what I do.
Is the motor carb'ed or fuel injection? Like I said I'd pump out the gunk, not run it thru the motor. Once the gunk is cleaned out I'd use a 10 micron fuel filter/water seperator.