In one text to me they claimed it was my responsibility to fix what they did because in the lease it states that THEY are responsible to keep the premises in a clean and sanitary condition.

Napkin math and assumptions are:$700/room rent~$2900 all in payment with taxes, insurance, etc at 5% down on a $325kWith an ADU you could also try and get more than $700/mo which is will improve the numbers.

Bought a house, without seeing it, at the local bar using a napkin to write out a purchase agreement.

They will commonly loan out at 12% and pay out at 10% (to give a back-of-napkin example), so you could be passive there.  

I included the napkin analysis from the owner.Excellent Business Opportunity for cabin rentals in Canoe Country, Noel, in south west Missouri.This beautiful area is canoe country with other popular outfits like Gracie's Canoe Camp, Kozy Kamp and Lazy Days.2 acres called Red Top, located off Highway 59, backs up to Butler Creek.

As you mentioned, debt paydown is a major oversight in most napkin-math calculations. 

I am a home brewer myself and it MUST be very sanitary.

Also the problem was a sanitary wipe tenants fault.

Purchase price: $68,000 Cash invested: $10,978 4 bedroom, 2.5 bath, ~1700 sq feet, 3 levelsLot4,791 sq feetYear Built1950Property TypeSingle Family ResidentialHeatingForced air conditioningAppliancesDishwasher, Dryer, Free-Standing Gas Oven, Free-Standing Gas Range, Free-Standing Refrigerator, WasherBasementUtilitySewer: Public Sewer (Sewer-Sanitary) What made you interested in investing in this type of deal?

TENANT(S) shall adhere to the Massachusetts State Sanitary Code as found at 105 CMR 410 - Code of Massachusetts Regulations.