You have the right idea, I would definitely make the objects like the gun pick up on collision. Your set up has my hands too busy. A+D+SBar was a new set up and I kind of like it for the basic movement but id you're going to incorporate the mouse (In my opinion) I should have to take my hands off the mouse to hit a key if I need to be moving.
Personal Preference so that's just me.
Keep pushing and thank you for sharing...