Two new files have been created to hold the code in a more organized fashion.
This file contains the code for the Googlemaps images and for the random code number generator.
This contains the initialization of a new custom page type, to display the creation caches.
A new database table has been defined, to store the information required for each creation cache. This info will be drawn on-the-fly to produce the .gpx and .loc files.
I have discovered that other custom page types in plugins often use another table. The basic page info is saved in the normal posts table. however, more information can be saved in the new table, using post_id as the primary key, making sure that it is identical to the post_id for the actual page. I have not found how to do this yet, but I am getting more confident.
I would still welcome help with coding this plugin. I do not see this as an individual project. The resulting plugin is going to be of use elsewhere.