  We introduce a scheme for preparation, manipulation, and readout of Majorana
zero modes in semiconducting wires with mesoscopic superconducting islands. Our
approach synthesizes recent advances in materials growth with tools commonly
used in quantum-dot experiments, including gate-control of tunnel barriers and
Coulomb effects, charge sensing, and charge pumping. We outline a sequence of
milestones interpolating between zero-mode detection and quantum computing that
includes (1) detection of fusion rules for non-Abelian anyons using either
proximal charge sensors or pumped current; (2) validation of a prototype
topological qubit; and (3) demonstration of non-Abelian statistics by braiding
in a branched geometry. The first two milestones require only a single wire
with two islands, and additionally enable sensitive measurements of the
system's excitation gap, quasiparticle poisoning rates, residual Majorana
zero-mode splittings, and topological-qubit coherence times. These pre-braiding
experiments can be adapted to other manipulation and readout schemes as well.
