What do you have in mind?
You'll need at least 7-8 days for the trip west (giving you your time in Chicago) -- just for the driving and adequate breaks during your driving days. Additional stops for fun will add time. If this is a round/trip, then the driving alone and extra time in Chicago adds up to at least 12 days. Again, stops for sightseeing are additional. With two weeks and three weekends, you could make this a nice trip including some sightseeing stops along the way.
As for fun and safe, what are your concerns? If you like driving and roadtripping, there's no question about fun.
Safety is up to you -- you can be as safe on the road as you are anywhere, as long as you use common sense and take the appropriate precautions not to be vulnerable. Same as you'd do in the big city! Bob