I have a similar problem with hiking/ski trips. People are often standing up against white snow, or a bright blue sky 10,000 feet or more in altitude (Mt. Bierstadt was 14k and a rich bright blue sky), and when you take pictures like that you either have to pick a middle ground or meter the person.
I'm still trying to get it right, but I tend to take the meter reading from my AE-1 Program then open her up 1 full stop (it will say 16, then I'll open up to 11, for example) to try to get better definition on the human aspect of it.
Personally, I'd say this: What's your point? Why are you taking the photo? Is it for the foliage? Or the sky? What is your main focus? Meter for that, and deal with the rest. Personal taste, though, and there is no wrong answer.
Your "problem" is not rare, and has a fairly easy solution. It is a classic case in which the use of fill light is the solution. Bring a variable-power speedlight and a diffuser with you. Use the shutter and aperture to properly expose the environment, and use flash power to properly expose the people once you have set your shutter and aperture. Remember not to exceed maximum synch. speed on the shutter.
"Truth and love are my law and worship. Form and conscience are my manifestation and guide. Nature and peace are my shelter and companions. Order is my attitude. Beauty and perfection are my attack."