@Lesley StollYou'll want to talk to a 1031x expert asap so you know exactly when the clock starts for identifying a new properties to exchange into. 

This will help identify any potential issues or maintenance needs.

Any big things that stand out quickly identifiable for when a home would be a bad candidate for a pop top rehab?

Our investigations, supported by reports from certified structural engineers and multiple masonry and window technicians, have identified defective masonry work as the root cause.

You should first identify an area where possibly you can come anywhere near the ball park of what you are requesting.

The first step is to identify a strategy, choose a market that aligns with it and establish a team that will be your core 4 to real estate investing. 

The key here is timing – you have 45 days to identify a replacement property and 180 days to complete the purchase.

If you're considering a 4-tenant retail development, I'll assume you've already performed a fair amount of the preliminary due diligence and evaluation such as:* identified actual demand for the product type in the market you are considering, along with supply in process within competition area to the proposed site.* understand current market rents for the type of tenant and construction you are considering, and at your specific location.* understand delivery timelines, TI schedules, and general construction process/permitting for you and the end users.* have identified the most likely tenants for the development in question, and understand the building criteria each have for spaces.If you haven't answered "Yes" to each of the above, I would recommend pausing until you have the above nailed down.

I found a $20k property that would have been a perfect flip, but I also have identified several $30,000 properties in my area that could be great projects.

Identify your goals - Figure out if steady rental income or maximizing long-term property value is your top priority.