  Majorana quasiparticles localized in vortex cores of a chiral p-wave
superconductor hybridize with one another to form bands in a vortex lattice. We
begin by solving a fully microscopic theory describing all quasiparticle bands
in a chiral p-wave superconductor in magnetic field, then use this solution to
build localized Wannier wavefunctions corresponding to Majorana quasiparticles.
A low-energy tight-binding theory describing the intervortex hopping of these
is then derived, and its topological properties---which depend crucially on the
signs of the imaginary intervortex hopping parameters---are studied. We show
that the energy gap between the Majorana bands may be either topologically
trivial or nontrivial, depending on whether the Chern number contributions from
the Majorana bands and those from the background superconducting condensate add
constructively or destructively. This topology directly affects the
temperature-dependent thermal Hall conductivity, which we also calculate.
