The format of the CSV files can be found by Searching (don't waste time with the Index tab) for "CSV" in the embedded help. For tracks (which probably is still for MM 2004 as there is no reference to the line styles in V5 :shock: ) it says :
Each Track line of the file is in the form:
TK01,Name,Category,visible, locked, n_points,closed_loop, color, partition_time, tick_interval, update_distance, update_interval
Each track is immediately followed by the required number of track points:
All the other data can be calculated from that (for example in Excel), although the calculations are not trivial (I think it has been discussed in some threads on this forum). For example the Lat/Long is in degrees so you can't simply use Pythagoras for leg lengths as you can with OSGB/UTM, etc.. AFAIK, the Altitude and (maybe) Speed/Course come from the GPS engine so may not (necessarily) be the same as on the map or calculated from Leg coordinates and Time.
But beware that many Garmins don't record time in their "Saved" track logs (you must use the "Active Log" data) so much less data is available to use for the calculations. More obviously, there also can be no Time/Speed data with tracks drawn within MM or converted from a Route.