I wanted to export a folder of many lists for a friend who is also using BaseCamp. Unfortunately when I do this, at least as a GPX file, the folder structure is not preserved. Short of sending him my entire backed up database, is there any way to export and preserve the structure?
BaseCamp now allows you (at least in the Windows version, afraid I don't know if the mac does the same?) to run more than one database, so if I wanted to do what you're wanting I'd create a new database, containing just the folder/lists required, back that up and then send it to anyone who requires it.