Michelle Adiba Ash quips that friends advised her to set up a tent along the Miami River after more than a dozen transactions so she’d have easy access to her assignments.

She’s returned repeatedly to the river, where a mix of residential, shipping and recreational uses allows her to trade limited inventory to buyers searching for optimal projects amid economic flux. Despite swings in the real estate cycle, she has sold more than a dozen properties—some more than once—as demand heated up for either income-producing marine sites during the downturn or developable waterfront parcels in periods of economic boom.