Ok so I bought my sewing machine yesterday and my bag is here now to chop it up. The way I'm thinking about doing this is basically just above the zipper sewing 2" rectangle the width of the bag then cutting the middle of it open and sew velcro to each of the loose pieces.

l__________________________l <--- rectangle to sew velcro inside of
========================= <---Zipper

Like that so I can get it nice and tight to the hammock and still use the bag if I go tent camping with my wife.

I'm new to the sewing machine so I was hoping you guys/gals might be able to give me some pointers or even if you have a better idea of how to achieve similar results.