For me...I would try to plan on meeting the guides at the earlier part of the day like at 10...just in case dinner could be a different location?
I thought it was expected that people would be arriving at the airport by 1, so it makes sense the tour guides would be waiting at the hotel to give the details of day one.
Our plans are to be back at the airport (we are staying on points at the airport embassy suites...free breakfast, free shuttle back to the airport, etc!) in the earlier AM, get picked up by the driver, and then delivered to the hotel by 10 or 11, giving us the rest of the morning and afternoon to wander over to the tar pits/Roosevelt hotel, to be back at the hotel around 4:30/5.