Yeah.  I figured those responses were coming, but decided I'd check anyways.    Thanks for the input.  It'll be a while before I have enough money to get all the gear for both independent backpacking (I have yet to get a stove, tent, or any type of water treatment), and then bikepacking on top of that, but I'll keep this advice in mind.  Take it easy.

Hey all,
I'm new to the forums and idea of bikepacking, but not mountain biking or backpacking on their own.  I'm purchasing my own mountain bike (after testing friends' bikes for a while) next week, and have been backpacking for almost a year.  I love both activities very much and much like a lot of you would like to combine them. 

I have a Gregory Baltoro 70L pack right now, and just for kicks am wondering if this is at all feasible for bikepacking.  I'd imagine not, given it is designed for standing, and not being more hunched over on the bike.  I'd imagine something closer to 25/30L would be more appropriate.  Does anyone use a large pack successfully?  Thanks!