This work addresses wave propagation in extended, inhomogeneous, multidimensional environments capable of channeling energy over many wavelengths. Sound propagation in the ocean and electromagnetic guided-wave propagation are two examples. The objective of this research is to further develop and apply "microscopic" phase space (pseudo-differential and generalized Fourier integral operator) methods and global path integral constructions to derive new multidimensional algorithms for forward acoustic propagation and generalized acoustic tomography at the level of the n-dimensional scalar Helmholtz equation.