I think the first thing you want to do is put together a gear list (doesn't have to be the excel spreadsheets many of us use, just a list on a piece of paper is fine.) Since you'll be going solo, and away from campgrounds, you'll have to carry everything you need - you may have shared gear before, or lived out of your vehicle, and may be shocked at how much stuff you end up needing to carry.
I always found that Colin Fletcher's "House on your back" concept worked well. You need a bedroom, a kitchen, a pantry, a clothes closet, and a bathroom. Think about what you need to eat, sleep, be warm, and take care of your personal needs, and list the gear accordingly.
After you've got your gear list together, pull out all the gear on it and put it in a pile. It will be surprisingly large. That's when you start asking, "What is a necessity, and what is a luxury?" For example, if you've got frozen steak, whole potatoes, and canned pudding in the pantry, and a grill, stove, a couple pots, and a plate and cup in the kitchen, the question becomes apparent: How can you reduce that? Well, by eating a freeze-dried pasta entree that you prepare by adding hot water to the bag instead of steak, baked potato, and puddding, you eliminate a lot of food weight - and the grill, the plate, some utensils, and all but the stove, one pot, a spoon, and a cup from the kitchen (and, with the right pot, you can eliminate the cup.)
The same logic will apply to all the other "rooms."
Once you've made that first cut, it's time to load it into the pack to (a)see if it will all fit, and (b)see how much it weighs. Then you can start asking specific questions here, about specific packs (if you need a new one) or how to cut weight (with lots of recommendations on lighter, better-suited gear.)
I apologize if I've spoken "down" to you, and realize that you may have already done some of this since you use walk-in sites. But, since you said you were "new to backpacking," I asumed you hadn't done any of this yet.
Let me know where you're at in the process of assembling appropriate gear, and we can move on from there to discuss planning and taking your first solo trip.