In this paper, we offer a simple but general framework for analyzing the statistical properties of mobile-to-mobile (M2M) fading channels. Differently from other contributions that can be found in the literature, we are interested in end-to-end performance metrics rather than in simply analyzing the statistical behavior of the so-called product channel. As a consequence, our proposed framework is suited for system-level performance analysis of channel dynamics in multi-hop wireless networks. In particular, we report a general framework for computing the spatial auto-correlation function of the end-to-end Signal-to-Noise Ratio (SNR) over Log-Normal shadow-fading channels. The accuracy of the proposed approach is also substantiated via Monte Carlo simulations.