It is my personal pref. that outhauls and travelers are not "internal mechanisms". Your in a race or in a lot of breeze and your outhaul line breaks, but it is run internally, thus very hard to fix. An exterior track is much easier to fix. It may not look as clean, but I believe in it.

A Harken traveler car and a 7" piece of track is not expensive when compared to a 7 or 8:1 mainsheet or even re rigging with spectra lines or a possible re-cut of a sail.

40' of standard dacron mainsheet line wet, hanging from the boom weighs more than a traveler car and a small aluminum track.