I'm not a yoga instructor so I can speak freely and say she might do well with some downloadable video (very small fee) of her leading someone through poses appropriate for a small space like an RV or office (since she'd be practicing in there anyway!) and you might benefit from something similar in sustainability realm. Passive income, yay! do it once and rake in the dough (ha ha) in perpetuity.
If she goes for this idea, have her buy a domain and get a webpage hosted. use wordpress (or other that allows profiting) as the WYSIWYG program so she can affiliate some GAIA products on her page for even more dinero. blogspot is or was not affiliate friendly. Oh, and have her set up a paypal acct so she can put a 'support me' paypal link on her page (yours too!) Also a great place for her to put some written words...we'd love to benefit from reading her excellent prose!
And a youtube account (she already has one, right?) where she can publish some free stuff to build interest.
good luck and have fun.
for those of us running a website for profit take a look at this article if you want to increase your views (**NOT MY WEBSITE**):