$GPVTG,000,T,344,M,00.0,N,00.0,K*4D

Probably my bad. A lot of the code is based on whatever I could figure out from other applications like gpstrans and gpsman (a TCL/TK app). I'm guessing I misinterpreted my sources on that VTG sentence. It should be fixable by adding a couple of 'skip(&p);' entries in the right places. Doing that now...
And I'm sure that the GGA parsing works fine if I change the strtol to strtod in nmea_time.

I implemented both TSIP and TAIP based on reasonably official looking PDF documentation that I found with Google. But as I never ran the code it most likely doesn't work yet. (For Garmin I worked from their official specs and it turned out that I had the whole checksumming stuff wrong)

Python script, ehh, python parse_mapsonus.py route.html, just did that on the file you attached and the route file it spat out is attached... (It's binary, so I hope it doesn't get corrupted by attaching it)