Lo, not having done an RS tour, I can’t offer any experience there, but September of last year, we started a coastline/clifftop hike 5 miles to the east, and made our way to the causeway, in ferocious wind, accompanied only by outstanding views the whole way, some ascending and descending, a few sheep, and only a half dozen people in 3 hours of hiking, all going the other way. We didn’t actually stop into the visitor center, and even in the semi-off-season, the causeway itself had quite a few people. It was really a contrast to the windswept isolation during the hike. After 45 minutes on the causeway stones, we caught a Rambler bus back to where we’d parked our rental car, for the drive towards Belfast.
If you’re up for it, after enjoying some time on the fascinating hexagonal blocks of stone down at sea level, hike up to the east, for a higher view, and to get away from the crowds for a moment. You don’t have to go far, and then turn back around, but it’s steep. Worth the effort for those with the time, energy, and mobility.