Rick, wow, what a great idea. 14 is a cool age for the autoshow and to stay downtown during the show is a huge idea.
The show is a super busy time, so your choices downtown might be limited, so book your room NOW. The Antheum is fabulous but the cool place for a 14 year old is the Ren Cen. It is like an escher print in real life.
Staying in the suburbs and driving in will assure your son of a lame time, whereas ridding the People Mover to the show will be cool.
Safety is not an issue downtown, and certainly not during the Autoshow. One it is cold so petty criminals stay inside, and two, there are more cops down there than pigeons on a statue. Those folks that are warning you to stay in the 'burbs might not venture downtown as offen as I do - especially during the Auto Show. Downtown is very safe.
Oh, make sure you bring your passports, or at least birth certs, etc. becaue you must take a day trip across the River to Canada. If your son has never been out of the country, this is the perfect opportunity.
So, in conclusion, stay at the Ren Cen if you can get a room, ride the People Mover around downtown and take the shuttle buss to Canada.
Your son will be telling all his pals about the cool things he saw and did while in The D. He might be blase with you, but with his pals he is going to be the coolest, baddest kid in school if you stay downtown.
email me if you need additional info.