I think it would be pretty cool to have the HQ in a mountain or underground and the above island be a resort, or a hotel or the like. Some place that can be used for cover and make the team some cash (just like Walker has office buildings over his HQ bringing in the cash).
Have you ever looked into a mirror and wondered if behind it was another world, the same... but totally different? - Reflection (2002) UTOPIAN PRODUCTIONS