I feel even more overwhelmed about doing my own heritage album now reading this!
I would make it as simple as possible and keep it to one book per "side" of the family:
Aunts/Uncles with spouses
Their children (your cousins)
One each page, I would have their statistics and maybe a small story about either where they grew up or how they met their spouse or something simple.
I saw a really simple family tree ablum in an issue of CK a while back. You might find it on the CK website....