In Hawaii solar panels are a big deal.  

Not sure how easy it is to remove that old school wood paneling?

If you're going to install a new electrical panel, sewer line, or water line, this is the time to have that work done. 

It’s pier and beam, looks like some floor issues, in the main room has paneling, kitchen & bathroom needs redoing, probably a new HVAC (?).  

Has its own solar panel to keep it's battery charged. 

It needs  work , the roof leaks because a tin roof panel blew up during a storm and wasn’t fixed.

. $1,900 replacement)- Brand new replacement water heater then leaked less than 1 year later (was leaking for multiple days before I was aware, $2,500 to fix properly)- Old shower handle fell off, exposing old piping that was "about to burst" per plumber ($750 replacement) - Kitchen sink leak ($250 repair) - Old breaker panel replacement (approx. $2,000) - Fence post fix ($350) - New Furnace ($5,500) - Bird infestation removal resealing attic ($850)- New Vapor Barrier in crawl space ($975)Property #2: - New Water Heater ($2,000) - Repaired main water line ($950)- Hot tub removal ($600) - Tree removal ($1,235) - Bathroom fan replacement ($500) - Towel Bar replacement ($150) - New microwave ($450) - Pergola removal ($400) - (Due to damage from roofing materials crushing part of it during a strong wind) - New Roof ($13,695)I have probably missed a few items as well..... 

When you start adding up a new roof, mold remediation, basement water, new electrical panel, new furnace I would worry you are going to go past that 20K and I would consider a pass, but I don't know all the details like you and this is just a quick review.Also, you have $17,500 listed for closing costs which is very high.

How to remove the mold, should I use Drywall mold tough and how to watertight the house from outside.There were wood panels which caused to grow the mold. 

Btw, I went to a panel at a local KW office a few months back and found it to be very insightful and informative.