I thought my 140k rehab funds were plenty, but I found out the hard way that it would really take $50-$60 per square foot for the interior. 

Start ups are hard, expensive, and take a long time to get going.Have you looked on Bizbuysell, Crexi, or Loopnet, to see if there is one that is already going for sale?

Also, at this time I had seen properties selling for 10 – 20% over ask regularly.Interest Rate 30 year conventional 7%Homeowners Insurance = $1,000 annuallyRents = $1,800 per monthWhen I looked at those assumptions, I would need to put down $80,000 on this house to get it to hit my cashflow goal of $500 minimum per month which equates to 35% down.Total mortgage + escrow = $1,267.13 per month with rents at $1,800 my monthly cashflow is $532.87.From my experience, after taking out vacancy and maintenance costs you are left with around 73% of that total cashflow number once the rental is established.People have asked why a $500 per month cashflow goal.

Take @Frank Rolfe's MHU bootcamp!

Or is your plan to take their equity as your profit?

Quote from @Srini Rajamani:There is a lot of information out there and many paths to take.  

If you're unsure of any data, AI will take the best guess of industry standard for that particular repair.

I put roughly 20% down on a $200k home, and am curious what steps I could take to possibly turn my original investment into a large portfolio within the next 10 years, when we're currently "low on liquid funds" after finishing up a wedding.... 

For house flipping, consider an LLC taxed as an S-Corp to reduce self-employment taxes by taking a reasonable salary and the rest as distributions.

Especially for investors who are farther along in their investment careers & want to take a longer view (stability is also a factor) and have the cash to park indefinitely.