Dear all,
In case someone is interested Pat4-route (link goes to it's github page) contains, to my understanding and trial and error, the P4 route file format.
In the repo there's also a small Java program I wrote to test out my hypothesis about the format.
It reads a route file, then writes a new binary file based on the reconstructed Route, and also a text file too which contains the same data in human readable form for debug purposes.
The only tricky part is little-endiannes and char array max lengths.
Bye,
rkeeves