@Brendan Seals a new AC/Furnace here for that size house recently cost me 4k and last month I had a new 40Gal. hot waterheater installed and it cost me $1000 (which is up 20% over the last  year).

Unfortunately, I don't have enough capital right now to take it down by myself so I am talking to some investors on a partnership where they bring the cash and credit then I bring the deal, knowledge & skills to execute it, and some sweat equity as my company will handle the construction portion of the project.

If yours has nicer finishes but is smaller, you can assume a certain premium for finishes, but a reduction for size.  

They're all tied together, with Valassis handing urban markets and the east, Mspark handling "rural" markets and the Midwest, and Mailbox Merchant handling the West Coast, including its urban centers.I'm at Mspark, so each company will have a couple nuances specific to them, but if you wanted to run postcards, for example, you could do so to a blanket zip code, portions of zip codes, or even carrier routes, for $0.20 a mailbox.

Find a lender who can quickly tell you if have a chance at qualifying for this loan size.

Divide the work into 4ths and pay the draw when that portion of the work is completed satisfactory.

They are dictated by the immediate rental rates of the immediate area, and NOT some general average which includes properties that are not the same size and out of the micro-market formed by these comps. 

Based on size it is likely going to be a local that finances this unless you get them to seller finance.

I think the approach I'm going to go with is to simply allocate a portion of my profits towards enjoyment, I think that will keep me interested enough to keep building bigger but without getting burned out.

Biggest factor to inflation will be supply issues and size of national debt.