Chris,
Good to hear it is working for you with your Tru-Trak. Turn Anticipation is on our development wishlist.
As for activating a particular leg, that is not possiblt at this time. You can use the "Direct-To" option for the next leg, that will drop a point where you are and direct your TruTrak to the next waypoint. If this is a Flight Plan that you will be returning on, I'd recommend saving it before you start pushing the "Direct-To" buttons as it adds those turning point insertions, which might be a good thing.
I hope this helps.