Very few houses in the are offer a form of air con that isn't "provide your own window units."

Really think doing a house hack where you use a primary residence loan on a Duplex (like @jordan moorehead recommended) is an outstanding move. 

The plumbing test is only a pressure test with an air compressor and no effort is made to identify the problem. 

So lets start with a Cosmetic rehab-(lets say it includes) Updating everything in the bathrooms, updating everything in the kitchen, new paint, new floors throughout, new trim where needed, new int and ext doors, new light fixtures, drywall repair where needed, new outlets, landscaping clean up, putting in a few new windows, power washing the house, servicing all mechanicals, inspecting all electric and plumbing.Lets go by sqftSingle family:single story houses up to 1500 sqft- about 6-8 weeksSingle story houses 1500sqft-2500sqft- about 8-10 weeks single story houses 2500sqft- 3500 sqft- about 10-12 weeksTwo story house up to 1500sqft- about 7-9 weeks two story house 1500sqft- 2500sqft about 9-11 weekstwo Story house 2500sqft-3500sft about 11-13 weeksMulti Units:2 unit 2000sqft-3000sqft 10 weeks-14 weeks2 unit 3000sqft-4000sqft 14weeks-17weeks3 unit 3000sqft-4500sqft 15weeks-18 weeks4 unit 3000sqft-4500sqft 17weeks- 20weeksNow lets say it was a full gut rehab (all items from cosmetic) plus running all new electric from panel to the outlets, all new hvac forced air or boiler both heat and ac, and new plumbing through out.

I always check the big ticket items (driveway, roof, garage, air conditioners) before purchase to make sure I should be good for a few years while I build equity that I  can use to pay for those repairs in the future if need be. 

Other than, The home did not have any air conditioning at all besides window units, so that was a challenge in itself.

It's obviously not the best time to be focusing purely on air bnbs now due to no international travel and border closures

The people who bought in 2012 had it pretty easy and while they generally were the big winners they still could have ended up as losers if things changed for the worse.Regardless its really up in the air how the market will react to certain news and I think COVID showed that because despite a very uncertain future where most would think home buying would be on the decline, people are still buying houses because human behavior tends to react irrationally.  

@Jordan Deeney @Geoff K.According to the zestimates its worth anywhere from $90k to $100k.

I think Diego can answer all of your questions from experience but I would agree with Jordan's comment on the upper limit.