I've always lived right around Woodward and have gone to the Cruise off and on since I was kid. Now that I've gotten bored of the DSM Shootout (which is usually always the same weekend), I've regularly attended the DreamCruise the past couple of years.
The variety is pretty huge. It's mostly classic American/muscle stuff, but you'll see plenty of modern stuff, Euro/Import, exotics as well as oddball custom stuff, cars acting as political billboards and lots of brodozers rolling coal when they get the opportunity.
I have two spots that I visit that day:
-I get to park at a friend of a friend's business on the Northbound side of the road, just north of the 14 Mile intersection. I usually start my day here. There always seems to be a little less traffic at the spot (as opposed to going south between 11 and 14) and being at an intersection means you get to see a WOT pull every time the light goes green. IIRC, you can also find parking in the garage's in downtown Birmingham just up the road.
-The next spot I go to is what's called "The Loop". The Loop is the northern most point of Woodward, where if you're heading north it turns into a one way road that loops around downtown Pontiac and eventually puts you back going southbound.
The action at the Loop is very different than what goes on further south in places like Royal Oak and Birmingham. In those areas the event is well patrolled with lots of police officers on foot or bicycle ready to hand out infractions for burnouts and such. Pontiac however, can't afford to have it's own police force and relies on the county, which means there isn't as much patrol for the event. And the minimal police presence there also doesn't seem as "engaged" in enforcing what they crack down on further south.
That pretty much makes The Loop an unofficial burnout contest. It's probably not for everybody, but I would imagine your 15YO would get a kick out of it. I'm 32 and I think it's a blast. During the event, the Loop is populated by a real diverse group of locals who are chomping at the bit to step in the road and pour some water on the ground or hold the rear of the vehicle in place so it can to do a brake torque. My GF drives us there in my bare bones bolt ons RWD V8 Dakota and beats the tar out of the thing doing dozens of burnouts as we make passes cruising on the inside lane.
IIRC, as long the weather holds out, the loop stays active for longer since they don't kick the cars off the road at 9PM like they do at the southern part of WW.
The Loop is also just north of the new-ish M1 Concourse track where IIRC they had a bunch of events in the days leading up to and day of the Cruise. One of them was that whole FCA sponsored "Roadkill Nights" where they turned part of Woodward into a dragstrip and held a celebrity race event where Richard Rawlings crashed a Demon or Hellcat during a drag run. However, I think that was the weekend prior to DreamCruise weekend.
As was said in the previous comment. The road is pretty populated with cars on Thursday and Friday nights before the official event as well.
All in all, it's a good time, although I'd say my favorite large scale "classic" car event near that area is Frankenmuth AutoFest in September.