I'm now about 17 hours in at level 8 and I don't think I've stumbled across any of the main quest yet. I just found the Galaxy News guy and he told me he'd help me find my dad if I help fix his satellite dish.
Question: Do I ever get to sell any stuff? As things are now I just keep dropping things everywhere. I've found a few places where I can buy items but nowhere to sell them.
It seems you missed a place that I found early on, though at first I did wander aimlessly through the wasteland. That is:
the town of Megaton, with the usual RPG fixtures--tavern/inn, merchant, NPCs to talk to and get quests from. One quest there will solve your current problem.
Buying/selling, item storage and even a place to hang your hat are all in the cards for you. I cheered when I finally got dependable storage of loot. I was spending WAY too much time trying to decide what to sell or drop and what to carry around.
I'm at Level 6 now, and on my way to 7. I just did the part in your spoiler, and I'm now on a quest for someone in my spoiler. It took me a while to find my legs in this game, but now I seem to have settled into it nicely. I still stumble into firefights that lop off a lot of HP. As a result, I have become an accomplished save whore. I should get recognition of that with some official game perk, like a Quicksave skill.
I'm extremely impressed. The world is huge, and everywhere I go feels different in a meaningful way. Exploration so far has always been rewarding. My official game time is about the same as yours. I'm playing on Normal difficulty.
Edit: Oh, wait. I guess you did find it, but didn't realize you could sell. What K-man said. In order to sell while in the bartering screen, press LT (or equivalent if not 360) to move over to your inventory. Anything you select will go for sale.