A method using classical mechanics to identify exact resonance eigenstates of a reactive scattering system is presented. Semiclassical approximate eigenstates are first constructed from classical trajectories of a defining topology. The semiclassical wave functions then serve as initial states for an exact quantum time-dependent wave packet propagation. The quality of the initial semiclassical approximation is readily apparent from the extent to which the spectrum of the resulting dynamics is dominated by a single peak. The systematic construction of the resonant eigenstate spectrum in association with a progression through defining classical topologies is emphasized and the predictive implications of the method for approximating essential resonant eigenstate nodal structure and energies are discussed.