Hey guys! I was given this great bike, but sadly I just don't ride it due to my living conditions (top floor, heart of Hollywood- I want a mountain bike

So I was thinking of selling it, but then I realized I do not know the first thing about vintage bikes. Can anyone here help me appraise this so I have a better idea before entering that stage? I was told it was worth a fair amount, but I really have no idea. It rides really smoothly, and doesn't appear to have any issues other than the fact that it's old and could use a new paint job.