The structures of Ne-n-HN2+ for (n less than or equal to 17) and vibrational red shifts for (n less than or equal to 6) clusters are investigated. The potential energy surfaces are based on a rigid monomer ab initio interaction potential which has been modified using a vibrational adiabatic correction. In order to reproduce mid-infrared experimental results on the Ne-HN2+ dimer, the potentials describing the interaction between Ne-HN2+ (v(1)=0) and Ne-HN2+ (v(1)=1) are subjected to a simple energy scaling. The final potential energy surfaces reproduce all experimental observables satisfactorily. The dimer potentials are used in the calculation of minimum energy structures assuming pairwise additivity of the interactions. In larger clusters the neon atoms form solvation rings around the ionic core. Because the differences in total energies do not reproduce the observed vibrational red shifts, diffusion Monte Carlo calculations are performed to assess ground-state energies of the clusters. For n less than or equal to 3, the calculated and observed red shifts are comparable. However, for n > 3, calculated values systematically overestimate the red shifts. The discrepancy is mainly attributed to the neglect of many-body interactions and the marginally defined shape of the dimer interaction potential for larger angles.