So looking at the job in phases: Permit 500-1000 Demo 3500 - 5500 Sheathing repair 2200 - 3300 WRB 1200 2200 Vinyl - 600/square installed Not sure how many squares you'll need to do but I think you're looking at around 12k on the LOW end. 

Curiously, are you permitted for short-term rentals? 

Permitting the dwelling or grounds to be used for, or to facilitate illegal activity, including drug-related illegal activity. c.

I also bought quite a few 20 40 80 acre tracts and would bust them up as well.. it was pretty cool because in Oregon logging permits are a snap.. you dont need any county grading permits to bust in your logging roads so say I had a 20 acre that I was going to short plat into 4 5s we would put the road in the logical spot for each parcel future access and then put a few landings in the logical spot for the homesites all under logging permits saved THOUSANDS .. then sell off the lots..

Search for Zoning Permits or check the map of the Subdivision for a Quick results.

This was for a fully licensed contractor to do everything from pull the permits to get the materials. 

It would not be bankable at that price because it will not even make the appraisal and will not meet the coverage ratio on the debt more than likely.The extra land to expand story is as old as the industry has been around, and means nothing without an actual permit to build in hand, and even then you will need to price it out (around $20,000 per lot plus land cots plus tap fees and engineering).I would price this deal more at around $550,000, which is a win/win for both buyer and seller (assuming you can still push rents based on market).

We got permits for the egress windows.

Meet with the permits department prior to closing and consult with a architect.

Whether it's extreme rehab, quick closing/cash offer because seller needs it gone, or risk due to area/permitting/market timing