I put all rent proceeds into an account until I have 10k per house saved up.  

However, this requires building plans as well as a property inspection and thus is an expensive and time consuming process.

I currently have a 4 plex under contract and am at a bit of a crossroads whether or not I should try to proceed. 

The older a debt becomes the more difficult and time consuming it becomes for courts to sort out disputes. 

@Bill S. does he have to proceed with an eviction in Colorado in order to take back possession of his property?

Any buyer can walk in behind one of these frauds, make an honest offer, put down substantial consideration, and kick the unlicensed broker to the curb.From the statute:All contracts, options, or other devices not based upon a substantial consideration, or that are otherwise employed to permit an unlicensed person to sell, lease, or let real estate, the beneficial title to which has not, in good faith, passed to such party for a substantial consideration, are hereby declared void and ineffective in all cases, suits, or proceedings had or taken under this chapter; however, this section shall not apply to irrevocable gifts, to unconditional contracts to purchase, or to options based upon a substantial consideration actually paid and not subject to any agreements to return or right of return reserve

When I was young my dad said to build a house and sell it, then another, and another, until I could use the proceeds to have a "free" house!

Proceed with caution.

Here, I have seen HOAs take possession and then rent the property out on a month to month basis, using the proceeds to recoup their losses and profit until the 1st lien position forecloses.

That doesn't cure the nonpayment of late fee, so you still have cause for termination.However, if the landlord decides to proceed with termination on that basis alone, the tenant has at minimum 38 days before being evicted (can't give notice earlier than 8 days after due date + you must give 30 days notice) which means there's virtually no chance you're getting a rent check for the next month's rent.