If your budget will allow for a purchase of $400k or more, a single-family house within walking distance of the beach will likely yield higher return and a larger runway for appreciation.  4-bedroom channel homes in the popular Cherry Grove section of North Myrtle Beach go for around $600-$800k. 

If you're up for it, testing a small version of your idea could give you a taste of its popularity before diving deep into the numbers.

Gray is popular today.Sam Shueh 

Stainless steel is popular, but white can be more budget-friendly.

Real estate investing has become increasingly popular in recent years.

They are known to take a property subject to but that is not an assumption in spite of popular opinion to the contrary. 

Rentals in PC are popular, whether short or long term.

Claremont CA 91711 (check on Zillow if you like to see purchase etc ) (We are finishing the landscaping, driveway and ADU together)  ADUs are super popular near downtown columbus ohio as well with a council variance. did you do all the zoning and plans yourself or hire an architect or attorney?

Like Bjorn said, there are a lot of overpriced properties currently so value add projects have been more popular in the current market as you can get in much cheaper and create value. 

For example the city of Frisco is a pretty popular place to live today, population over 200,000, and I'll bet there are less than 100 duplexes.