I got this cheaper than wheelez and gets the job done. Just made some satablizer bars for it out of pvc and don't strap It down instead use some paracord string to a clip and clip it onto the eyelet for where that seat straps on so it won't slide off. Mounts in seconds and smooth through the sand Harmony Gear Stowaway Cart with Beach Wheels (Wide Pneumatic Tires)
https://www.amazon.com/dp/B00CBEU2DI..._fATPvbZFZ7DWY