We have several kayaks. We transport on various surfaces, but by far the most challenging is sand. We started out carrying our ocean kayaks until I thought my arms were going to be stretched to my knees, we carried two at a time. We then purchased the wheels like JollyGreen. They were great on hard surfaces, but were almost worse than carrying on the beach with soft sand. Next we got the Wheeleez carts with balloon tires and haven't looked back. I sold the hard tire cart on ebay. The balloon tires worked best on all type surfaces. Although, Wheeleez has changed the cart since our original purchase. They reduced the size of the tires, which causes the valve stem to pop out when a heavy load is on top. With the valve stem popped out, there is a worry it may get hit and cause damage. Also, the original clips that hold the wheels on were easy to knock off. We have done so multiple times and now have replaced them with spring clip versions. I keep a couple extra in case we lose one. Fortunately, we must sail and kayak with honest people because nobody has walked off with the carts when we were gone. If we have a concern, we do cable them together and to a solid object.
We use a Yakima carrier for our pickup truck to transport the kayaks. Since we are both a bit vertically challenged, we have had to be creative getting the kayaks on and off the truck. The person that recommended and sold us the rack is a bit taller. Less than 5'6" and a stool is helpful.
Another point, I can get my AI on and off the Wheeleez cart by myself. I am 5'2" and petite. I can also put the AI on the truck rack myself, but I have to be a bit more creative.