I think you should plan for an hour each way... but on a good day, it only takes 35 minutes. You just don't want to do it during rush hour. You have no idea what might happen on the Dolphin expressway... a truck full of coconuts going to the landfill might flip, to even someone dropping a King Palm onto the highway (oh man, that was bad)... there's always an accident. You can always just take Tamiami Trail directly... but either way, I agree on going to the Miccosukee Indian Village to do the air boat ride. In my opinion, they have the best one. They also own a little island where often times they'll hold a BBQ out there... well worth it in my opinion. There's a lot of options if you reach out to them ahead of time.