Tom:
Not only can an 11 year old be kept in the garage, (with certain necessary modifications), but, as the step father of a soon to be 11 year old (birthday in February - I've been on the scene since he turned 4), I can assure you that the typical 11 year old boy would find it cool, especially if it means he can stay up late and play his game boy! So it sounds like your gettin' married or something! Congrats! A piece of unsolicited advice: Don't underestimate how important it will be to keep spending time on your music. Playing is great therapy and will help to keep one's sanity when the inevitable stresses of family life become a bit overwhelming. Great idea about keeping the bass and rig for the boy. I keep telling my step son that if he ever gets serious about guitar, he's going to inherit a helluva collection. So far not much interest, though. He learned a few chords and stopped. So enjoy the life voyage into familydom, assuming I'm not completely off base. And don't be a stranger to these here parts.
Bill, tgo