Since I was a teenager after watching TAR, I've been interested in traveling and racing, especially orienteering, and I'm glad there is a startup company modernizing this activity in a world where we are all consumed by digital info and addicted to Google (especially Maps for directions). This sounds like a fantastic weekend activity for people of all ages! A girls' trip/Saturday for the boys, family outings, co-worker join ups, etc. If done right, this could be the next "hot" experience game like the escape room. I checked out your website, I really love how in the "solve clues" example, the clues are cryptic and are not Wikipedia or Atlas Obscura-able, and that definitely challenges individuals or teams to build rapport and collaborate.
As for suggestions, I would highly recommend, if you haven't done so, gather as many sponsors from local, trusted businesses to support and help spread the word. The more people who know about these events from an already established brand or business, the more potential clients who will want to register for this adventure. The most important thing a new entrepreneur should do is promote intelligently and effectively. I've noticed an individual ticket costs $100+ including fees. Do you use Groupon or use promotional codes? Do you invite morning radio personalities from hit and Hot AC music stations to attend a race over the weekend? Do you have an app to enter the "clue portal" quickly? Do you go to any festivals and set up a registration booth? Any reliable source that will get the word out helps.
I would even go as far as hosting this activity in smaller cities like university towns (Champaign, Illinois; College Station, Texas; Auburn, Alabama; Stanford/San Jose, California; etc.) since I feel like college students would LOVE an adventure over the weekend after a week full of tests and long, dragged out lectures.
For race designs, I would stay down-to-earth and go to neighborhood eateries who serve a certain style of food, unique entrepreneurs (local gyms to do a workout challenge, locally owned crafts stores to recreate an art piece relevant to the area, beautiful panoramic sights, etc.), and make the race worth the $100+ I, a potential customer, am paying for. I would love to touch, feel, sense, and listen to the quirks and beautiful aspects of the city rather than just taking a picture and solving riddles which does waste battery and data in places with no free wifi. For example, let's say Miami will have a race: I would love to experience South Beach in a way that makes me want to learn something tangible (like DJing, beachcombing, mobile spray tanning, etc.), I would also love to visit Little Havana and recreate a mural on canvas or do a blindfolded eating challenge in memory of the Catharsis Restaurant that used to run in the district, and I would love to explore the Everglades spontaneously by going to the nearby alligator farm and "invent" a special alligator treat for the zookeeper to give the alligators at feeding time, then ride an airboat in celebration of finishing the challenge! Memories to talk extensively about indeed!