Share stories, share your thoughts, share your ideals and values, but don't lecture. Just talk about yourself and your own feelings. Stories about your experiences with her when she was little (things she likely wouldn't remember herself) would be great as well.
As others have pointed out lecturing and advice type videos will likely not sit well with her, cause undue burden or distress, or simply be ignored. If you want to make some videos like that you'd want them done in such a way that she wouldn't see those until she was in her mid-20's, about the age most of us started to finally mature mentally and emotionally and could actually accept, even crave, that sort of advice.
I like the idea of an extended trip. I'm not sure about pulling her out of school for it, but if you feel you may still be okay come time for her summer vacation, plan something then. Don't make rigid plans, either--nothing makes a trip more stressful than strictly scheduling every moment. Just say you'll travel some rough route with a few places to hit, but no firm dates--a classic road trip.
Most of all, don't totally give up hope on yourself either. Until you're actually in the final stages with organ failure there is always the chance that (real medical) treatments may still win, or at least heavily delay, what seems inevitable right now.