I just started using TopoFusion yesterday and already have collected various routes that I have hiked or are planning on hiking. Some for training, some in Ohio, some in Virginia, some in Pennsylvania, some in Georgia, etc... Rarely when I am planning a trip in Georgia do I care about wading through my local park hikes, the hikes in Pennsylvania, etc...
The feature would be the ability to save a file that could be as simple as:
ENABLE C:\Abc\Def\Xyz.gpx
DISABLE C:\Abc\Def\Abc.gpx
ENABLE C:\Abc\Xyz\123.gpx
When loading this file, TopoFusion would Unload ALL loaded files and load these files automatically setting the "Enabled" and "Disabled" checkboxes.
Then one can use the "File > Open Project", "File > Save Project" and "File > Close Project" menu items to Open, Save and Close these project files.
A simpler to develop, but not quite as versatile option, would be to add an "Unload All" button to the Active File List area right below the existing "Unload File" button. There is already an "Add All" button. This would allow one to (which I currently do) make directories such as "Training", "Local Hikes", "Weekend Trips in Georgia" directories containing related GPX files. Navigate to that directory, "Unload All" to unload all files and then "Add All" to load all the files in your "project" directory.
Jeremy