We purchased the property in summer of 2017 and had to borrow some of the money in the first place just to complete the initial transaction. 

Until borrowers can obtain financing close to the mid 2000s apartments will be the way to go for most people.

I had a few $K and borrowed the rest of the DP from my brother and sister.I sold it on a wraparound mortgage for low 70's after reading Wade Cook's book Real Estate Money Machine.

Still, seller financing is usually faster and easier to get than a government-backed mortgage—if the seller is willing and able to provide it.And, while most owner financing requires some form of background or credit check, it can help otherwise unqualified borrowers achieve homeownership.

My first draft of a plan is to borrow in the neighborhood of $150K from an investor, put 5% down and live it in myself, and build a backyard ADU while putting sweat equity into the main house through tiling, replacing/refinishing cabinets, installing new flooring, etc.

You also can borrow from your 401k.

Pull it off the market immediately and fix everything, borrow money from a parent or friend if you have to, but fix it and give it a month off-market so it can reset.

In this case, I borrowed 90% of the purchase price AND repairs which meant I actually walked away from closing with a check from the bank.

If you do nothing with the remaining $65K and once you pay off the $35K you borrowed, then you're back up to $100K in "available funds" and you can start the cycle again.

borrowed from my local bank to purchase property and used my personal cash savings to build hookups and bathhouse office area.