We investigate via optical (viz. linear extinction and nonlinear second harmonic generation) and non-optical methods (viz. helium atom scattering) rough alkali cluster films, which are formed on dielectric substrates. The application of nonlinear optical methods to these systems allows us to obtain real-time dynamical information on the time-constants for laser-induced desorption and for the decay of the elementary optical surface plasmon excitation into single electron excitations and finally into lattice oscillations of the clusters and the substrate. The combination of linear and nonlinear optics also enables us to deduce structural information about the morphology of the cluster films, which--in the submonolayer regime--is complementary to information deduced from atom scattering data.