Since the conventionally accepted explanation for the artificially induced shutdown of the US economy was to minimize human interaction in hopes of dramatically reducing the R0 of the coronavirus pandemic, and force social distancing during the period of potential covid incubation to prevent its spread among the population, it stands to reason that states in the US that are most at risk from a second wave of infections once the economy reopens, are those where a high level of physical contact makes social distancing difficult if not impossible.
To quantify said risk, Deutsche Bank has analyzed US states from the perspective of contact intensive occupations, and broken down the results in terms of low to high "contact" states. The results, shown in the map below, demonstrate which states have the highest risk of a new breakout (in black) and where an early reopening (light gray) may not have adverse consequences.
Putting the above map in context, here is a separate analysis from the The Institute for Health Metrics and Evaluation at the University of Washington, which predicts the "ideal dates" to relax social distancing.
Those worried about a second, more powerful infection wave - a la the Spanish Flu - will want to focus on the states that are dark in the first map and light in the second - that's where the risk will be highest.