In the UK there are several cave registries, one I use fairly regularly is the Mendip Cave registry, may be you could contact them for advice?
It seems your source data is an Excel spreadsheet, make sure that is formatted correctly if you are going to import that data into a GIS. You talk about "tabs", tabs in what, Excel?
I personally would move away from Excel as soon as possible as Excel allows you to write anything anywhere so people do (and that includes you)! This has ramifications on querying the data, so I would move my data into something like MS Access which enforces data integrity, i.e. you can't put a question mark into a field that is expecting a number. Excel will allow this and is bad.
You are describing a relational setup, a master table with the basic information linking to other tables, e.g. one cave can have many entrance each with different land owners. This sort of relationship is easy to build in Access or other database systems.
By maintaining an unique ID for the cave system this would allow you to associate other datasets like survex files, scanned field notes, reports that would not necessarily be able to store in say Access, so you need to think about the file system structure that you are going to implement.
A simple Google search throws are many cave databases I would suggest you trawl some of theses and get a taste of what sort of information is being recorded?