Purchase price: $20,000 Cash invested: $20,000 Sale price: $85,000 While searching for land that had timber.

I paid cash for the lot and am looking to finance the build through a construction loan. 

@Alex Silang Yes, whether your short-term rental can work as a long-term rental depends on location and demand.

Purchase price: $20,000 Cash invested: $20,000 Sale price: $85,000 Searching for land that had timber.

Since you're a cash basis taxpayer, I think the rule is that you can deduct the full amount.

need massive power close to said land.. also keep in mind they employ very few people so its not a long term thing for employment

It might be best to divide your cash from the sale into a down payment for a new primary residence and a down payment for a cash-flowing property in the area. 

People look to Detroit for cash flow, and you can definitely find it there, but the median price has also doubled in the last 5 years.I would not be surprised to see it double again in the coming 5+ years too.

Are they paying below market rent because the landlord hasn't increased rent over the years (eg long term tenants with no increase) or were they rented that way (ie low rent either to fill or because landlord didn't know what market rent was)?

here's another anecdote. it's often stated that short term rentals are contributing to housing unaffordability.