The desk is located in the main reception area, between the regular desk and the concierge. You really can't miss it.
They will weigh your bags (we had one slightly over and the guy advised us how to shift a few things to meet the weight limit), get them to the airport, and provide the boarding passes. I believe you need to check in w/ them several hours before your flight.
You can also leave your carryon items, if you have a later ME pick up and want to visit a park or do something else in the mean time, not at RAC, but in the Luggage Storage area (no charge). We did this as our ME was at 1:40 p.m., so we went and did Mini Golf in the morning.
Have a great trip!