You're welcome!
I think it's really important to keep in mind that, while you have one end goal of having these pages rank well in Google's results, the guiding force for creating them should be to convert human visitors into customers.
Service Area Business like yours (or like house painters, visiting home help, etc.) don't have branches that serve as the purpose for creating landing pages. Obviously, when a brick-and-mortar business has multiple locations (like a restaurant franchise) it makes total sense to create a unique page for each branch so that the customer can see the info they need about each branch. But when the business has an SAB model like yours, you want to be very careful that any landing pages you create have the purpose of serving people, rather than simply serving search engines.
This means making any locale-oriented landing page very specific to the locale it represents. For a business like yours, showcasing the parties you've done in X county would be a natural way to do this, along with testimonials/reviews from clients in that area. Any other approach risks watering down the quality of your website. You're lucky to have a fun industry that should easily lend itself to great, unique content!