MarketPress customize My Cart / Checkout page

Ok. I'm getting this slowly.

I've got my mp_cart.php page over riding and I'm thumbing through template-functions.php to try and find out how to rebuild all the default cart options. Is there an easy way to find all of these functions or a spot in the file that shows how the page is built in particular?

I've found mp_show_cart() and _mp_cart_table() but neither give me the full functionality of the default one. That being said - I thought I could go in an add a store/shopping-cart page but the content isn't automatically pulled into this page loop either.

At this point, I basically just need to add [mp_cart_link] and the Checkout link to my order / checkout and confirmation pages.