Did she like the Little Women? There's more in the series, you could get Little Men, do "series" or pairs of a single author like that, make it a tradition? That would give you time and goals :-)

Alice in Wonderland/Through the Looking Glass?

Personally, I loved the Chronicles of Prydain by Lloyd Alexander, there's 5 in that set.

I have a good used book search engine that I use to find my out-of-print books (or 1st editions), http://www.addall.com It searches most of the Web including eBay.

Or, get her a nice Amazon or other physical bookstore gift cert and the two of you have a day out together at the store?