I can highly recommend Rothbard's MES. I found it easier than Human Action. Not only in writing style, but also because Rothbard dares to finish some of the conclusions that Mises left open.
For example: Mises left the entire question about the size of the state open. He advocates for minimizing the state, but did not finish the thought on what a society without a state would look like as he still considers protection services best to be provided by the state.
MES gives you the theoretical basis that there is no need for the state. Several other books by Rothbard go into more detail how a society without a state functions (both predictive and with plenty of historical examples).
I'm still learning and reading. In terms of modern Austrian's, I can recommend Hoppe with some new refreshing takes.