Another from more or less stupid ideas about "what to do if everything will be done". Having website with all these stuff is just great, but to have public API, accessible from mobile application (I don't think you plan to create whole new mobile application, or?) to search for caches around with some advanced use cases that are not provided by geoching website or their "API".
Use case I have in my mind:
Search from coordinates similar to "Map Compare" to return list of caches around that neither of group or some of group didn't find. This can be handy to have when you are caching with friends and without preparation and you don't want to download every cache, check it for logs or downloading caches for all the people and doing some aggregation on client side.
I don't think this would be too much work, because you have all the sql queries, but the only thing missing is to define API and expose it. I can think about some JSON with list of caches with additional flags who found it if required.