Purchase price: $85,000 Complete gutted single family home on double lot acroos from Buffalo Lake.

I suspect your gut instinct is spot on.

Do you rely on specific data sources, gut instincts, or perhaps a blend of both?

Fight your instinct 

Trust your instincts, and if it feels off, it’s probably worth considering other sponsors.

Flooring, Drywall, refinish basement, roof, gutters, tuck point around house, and one full bathroom gut all had to be completed. 

You must not follow your instinct and attempt to invest as little as possible into the renovations thinking "If someone is willing to live in this neighborhood there is no way they have standards". 

I trusted my instinct that J Tree values would go up.

The website 51west.properties also scores low on scam advisor ("owner is using a service to hide their identity, high number of suspicious websites on the server, registrar has a high % of spammers and fraud sites, website is (very) young, website appears to be hosted by a company with a bad reputation", all according to https://www.scamadviser.com/check-website/51west.properties...)Trust your instincts. 

you just have to estimate them based on what the property needs.so if it needs a new furnace + a bathroom gut and remodel + new windows, you estimate that.