Our Heroine is an interdimensional traveler. Most places she travels are some variant of standard fantasy medieval-ish tech level, and she needs to be able to physically pick up and carry all of her worldly possessions at once, for brief periods. She also needs to be ready for a relatively wide variety of conditions (heat/cold, weather, hostile territory, managing a passing approximation of "local" clothing...) Also, though she can have things originating in higher tech levels, everything has to at least pass casual inspection as being medieval-ish. She has some magic, but generally needs to reserve her power for Truly Important things.
Her pack needs to contain, in addition to survival necessities, a book (a bit larger than a modern hardcover novel), whatever tools she would need to work as a tinker, whatever tools she would need for fairly basic/primitive jewelry making, and a small stock of trinkets/fripperies/trade goods.
1. What would she absolutely have to have? What would be Extremely Useful, and probably worth the weight? Is it plausible that the bare necessities would be within the weight that she could pick up and carry? (assume typical human strength)
2. Would it be plausible for her to have a pack that converts into sort of a little wagon (like wheeled luggage)? If not, what would be the most plausible way for her to shlep stuff when she's wandering about in-world, without sustaining massive back problems/falling over? (beasts of burden aren't really an option)
Edit: thanks for the help so far. More details in a comment (currently) at the bottom--specifically,
here