Good mixer for brandy?!
Answers:
I have heard that Caipirinha is made with a type of Brazilian brandy, and it has lime and sugar in it. So I would think lemon would work as well.
Although the definition of brandy is pretty general, and I am not sure what kind you got.
Actually on the link below there are three recipes for brandy with lemon, so I think your instincts were right on this time!
http://www.ehow.com/how_5106717_mix-drinks-brandy.html
Apple juice.
You have got to try Brandy and Babycham - FAB !
Dry ginger ale