In reading your post, I noticed two things that seemed important.

1. You are just getting started. WIth that in mind, I wouldn't invest a ton of money in a new backpack. I would first try to borrow one from someone...or pick up a nice older external frame pack at a yard sale. (There is a nice one at my local thrift shop for $6.50--I know, because I donated it!) Don't spend $100 on something you may only use once, because you find out that you really can't sleep on the ground, poop in the woods, etc.

2. You are talking about weekend trips. While some people will tackle 20 miles or more on an overnight, most people think of a weekend trip as something relatively short--maybe only five miles or so. At normal hiking speeds, this is only a couple of hours, maybe three. YOu can endure a lot of awkwardness for two hours. Try it out, see what works, and then invest in a nice new pack--although you might well find that you'd rather invest in a nice warm sleeping bag, a nice light tent, or a nice reliable water filter before you go for the backpack.

And you won't know that until you take your first trip!

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