Hey Robin :) :)
This is what we've done the past two years with gold medal results. About two weeks before taking the exam, we do one of the tests from the past 10 years (you can print them out from the NLE website). Then we go over the answers, and that's "it" for her Latin for that day. We do that for two weeks and then she takes the actual exam. The material seems to recycle through the exams, or else she's a good guesser :) Last year we did get some books such as Usborne Rome from the library - but we decided it was just too much of a shot in the dark to try to guess what they might ask.
I just realized this is the homeschool version of "teaching to the test" :biggrinjester: