You're not the only one that is nervous. I'm almost tempted to say I don't want a Han film at all due to so many things that could go wrong with the casting (I know, I know...I'm falling into the stereotypical fan rant here, but I can't help it - Han is my absolute favorite). One thing that I've seen mentioned in another thread that may help to ease the blow, so to speak, are bookends featuring Harrison Ford as an older Han - kind of like what they did with The Hobbit. In terms of when they might set the film, I could see them exploring his smuggling days prior to ANH, so I would say early-mid 20s, maybe? Although, if they go with the whole 'origin' thing, I could see them possibly going back even further.