Help me plan/time my gameday BBQ (baking then grilling pork ribs)

I've decided for tailgating Saturday I'm going to do some pork ribs. The (GT) game kicks off at 3PM which means ideally I would like to have the tailgate set up between 9-10.

As for the food aspect of it, I would like to slow bake these ribs for tenderness. I've already got a homemade sauce recipe I'm going to put together, but it's important for me to determine how I will time the slow cooking. My hope is to throw them on the grill for a few minutes right before serving to get the smoke and final effect.

My question is that if I plan to cook it in the oven around 225*F for 4 hours, do I need to time the slow-cook process to immediate move them to the grill? What would you do? What's the best way to manage my time to where I'd have them done cooking in the oven before departing, and time it to where I can load them on the grill at the tailgate around 12:45?

Basically, I want to know a way to take some baked ribs to a tailgate and sit around drinking beers between 9:30 and 1 PM and then throwing them on the fire for the final grill.

Is there anything wrong with that? Clever ways to manage balancing my desire to tailgate all morning/early afternoon, with delivering delicious ribs?

ETA: In case it isn't obvious, I will have a grill for the final hoorah at the tailgate site. I will also have access to the fraternity kitchen if I need to keep them warm. But I intend to do the slow cooking at home and take them with me to the tailgate hours before I plan to fire grill them.