The cost of installing an  expansion tank kit ( Expansion tank, auto fill with backflow preventer and air eliminator) is 1,100.

Trying to meet and exceed expectations isn't easy, that's why we NEVER stop improving:)

If not, kind of up in the air but I would at least offer to split it as you are both getting something out of the deal.  

We keep track of property expenses - all maintenance expenses, improvements, and business expenses, as allowed in the tax code (like a subscription to Wall Street Journal and lunch with other investors). 

Consider air sealing on the interior?

Is that central air that needs to be replaced, a new compressor?

Even if they play hard ball, from your numbers above, you'd make about a 30% return on the improvements- that's not bad when coupled with good cash flow. 

Lot of work for not a lot of grapes, too.The Air BnB/glamming is a good idea and you can still maintain Ag status by doing some other stuff on the property. 8ac almost seems silly small to be irreversibly zoned as AG, I’d look seriously into getting rezoned.

Use that as a template and improve as needed:)https://www.biggerpockets.com/...

It can only be deducted if used on the same subject property for capital improvements, which you say you don't plan.