I'm curious - how much do they charge for the classes, and how much per hour after that?
You can probably do basic meandering on your quilt right after getting the 2-hour class, provided someone is around to help if you have questions. You may even be ready to try leaves, swirls, etc. If you've done some FMQ already, the patterns that you used for that will be fairly easy to learn on the longarm.
As far as loading the quilt, that really depends on the loading system the shop uses (pins or zippers or velcro or clamps like red snappers) and on how ready your top and backing are for loading.