What type of classes are you looking for? I get the sense that you are looking for continuing education classes. You could check the websites of various CEC providers for upcoming classes in your area. (Like AEA, ACE, etc.)
I teach a series of aquatic exercise class CECs for certified instructors. Beyond Basic H2O and HIH2O (high intensity aquatic exercise) on the Big Island of Hawaii. Instructors can take a Continuing Education Vacation (tax deductible as long as you adhere to the tax code). I do occasionally travel to the contiguous 48 when a fitness center wants to sponsor my CEC programs.
You might try contacting local Fitness Centers/YMCA/Parks and Rec to see if they have any instructor courses coming up.