A central problem in understanding the superconductor-insulator transition in disordered superconductors is that the properties of grains and intergrain medium cannot be independently studied. Here we demonstrate an approach to the study of strongly disordered superconducting films by relying on the stochastic nature of the disorder probed by electrostatic gating in a restricted geometry. Charge tuning and magnetotransport measurements in quasihomogeneous TiN nanowires embedded in a superinductor environment allow us to classify different devices and distinguish between spontaneously formed Coulomb islands (with typical blockade voltage in the mV range) and homogeneous wires showing behavior indicative of coherent quantum phase slips (with significantly smaller blockade voltage).