Hey John,
It is at least 730km I am aware of that, yep
The questions you ask would have been answered and discussed via PM, it is indeed not needed to have 20 Baseboards each side. What i've seen is that the DEM Routes - on the DLS by fishlipsatworks for example - are also about 100-200 miles sometimes, including a lot more baseboards each side than necessary for the NEC - this is not a 7500ft high Mountain Region.
If they are 200mb, their CDP size drops to about 20mb when exported from CM. I never had Problems importing files less than 512mb into any CM. So i dont really see the Problem here... (Or do you mean the files that TransDEM puts out?)
For doing it myself - well i once tried and failed with that program, it is not really what i want/need now, to learn another annoying difficult program. Thats why i asked here xD. Ok, if there is no other way, i'd may try to learn it, but honestly i have better things to do and would probably never get to start working on that route again. Lately i get really fast pissed off if something on my PC doesnt work how i want it to :hehe:
Also, i'd do it in TANE, but hey, i got a $200 Raildriver and i want to use it haha ^.^