You mentioned kitchen gadgets -- how about stuff for a camping kitchen? Folding spatula, Lexan utensils, mini salt & pepper shakers, etc. Or maybe: mini sunblock, hand warmers, small good-quality compass.
This isn't really sub-$20 range, but how about an "IOU" coupon for a nice day hike together and a dinner out afterwards wherever she'd like?
Good luck! It isn't easy... <img src="/images/graemlins/smirk.gif" alt="" />