The fcc polymorph of the hyperexpanded fulleride Cs3C60 can be driven to a bulk suprconducting state without symmetry change by the application of pressure. Its Tc passes through a maximum of 34 K at ca. 6 kbar. We have been recently successful in isolating the isostructural Cs3-xRbxC60 family of materials with 0<x<1 in which the effect of physical pressure is mimicked by the application of chemical pressure through isovalent substitution of Cs+ by Rb+. With this proposal, we want to address the nature of the electronic states of the fcc Cs3-xRbxC60 phases at ambient pressure as we cross the metal/superconductor-insulator boundary. We will search for the onset of long range antiferromagntic order by using the muSR technique in its ZF/LF variants for the insulating phases (small x) and characterise the superconducting state for the metallic phases (large x) by using TF-muSR.