If your primary focus is to flip housing then a hard/private money lender is your best bet. 

It appears properties on probate can either be sold privately or through public auction.

Solid info. provided by @Michael LeThe biggest impediment for most people is personal balance sheet.

And never pays as much as you think it should when you do.So, biggest issue when buying, is it on special form.

The biggest one is Turnkey investing.

I saw a Facebook ad for something called Hipcamp, essentially an AirBNB for camping sites, public and private.

But if you do want to speculate on major neighborhood transitions than Bayview and the hunters point shipyard will be the biggest transformations in SF over the next 10 years.

After the last crash, Private Equity companies were doing this with a flawed model so they saw great losses, these companies are trying to use a more refined model however I still see gaps, the big upside is if you gave people the option of using a well known brand like Redfin or using the stranger who direct mailed or cold called you, Redfin will win most of the time over for those who are on the fence or uncomfortable with the situation.

While I was going to do 50-50 with the seller where I had the private deal, he did not have a realistic idea of the market value of his house.

Overall, I'm pleased with how the purchase has went, but I definitely need to be more diligent in the future as I start to use more of my own capital or private funds.