Solvation of ions at oil-water interfaces is so important in cell wall and enzyme function, colloidal chemistry, fuel cells, and other areas that substantial effort has been made to understand the process via molecular-scale simulations of well-specified model systems. Here we report a series of experiments probing ion transport and solvation in composite films that have a geometrical specificity that rivals what theory is routinely able to employ. Proton/hydronium transport across the water-organic interface has been studied using a novel "soft-landed" ion technique that allows precision tailoring of the interfaces (including initial ion position) and sensitive monitoring of the ion motion via the electric potential generated by the ions. There are two main findings. First, the ion solvation by water at the organic-aqueous interface is probed continuously for various monolayers of water present in simple and complex sandwiched structures. The potential trap created by the solvation can be systematically overwhelmed by the collective electric field of the ions, giving us some unique information about both the trap depth and shape. A simple Born model for the trap reproduces some, but not all, of the details experimentally observed. Second, ion transport in several organic glasses is well-predictable by continuum viscosity models at electric fields up to approximately 10(8) V/m.