And I've had comments about the loading time of the tiny and uncompressed GPSapp route files.

...not so much the loading as the disk spin-up delay occuring earlier than expected...

But your main point is certainly very valid. File size is an issue.

ISTR at some point you were researching geospatial file indexing schemes. Did anything valuable every come from this? I think that the ideal situation would be to be able to crunch all the data once and repackage it in a GPSapp-optimised filesystem tree which could be tar'd and zipped up for distribution.