Bryan, it seems to me that you are choosing to hike with your team, rather than with your "GF".
Have you already tried hiking with her?
How do you know that she would not be able to get to the top of HD?
Have you thought about starting with your GF a couple of hours ahead of your team and going slowly and steadily?
In this case she would get a better chance of reaching a sub-dome' and there she could make a decision whether to proceed further.
The most important is to maintain pace comfortable for her (not too fast).
