Great Mod! I was thinking of writing one like this but I still haven't got my head completely around the Smarty tags just yet. I am having one small problem that I can't seem to find an answer for...
In Step 7:
Your subtotal is ${$offerFreeGifts[ofg].minimum_price} or more. To receive a free {$offerFreeGifts[ofg].product}, click here
The "Click Here" link does not come across with any code...
This could be up to me and if so, just say so.
But as I am no expert with the smarty tags stuff, if someone has the code for that section I would greatly appreciate it.
Thanks and once again, Great Mod! 
Steve