I have a PA 14 also. I have the Hobie Trax 2-30 Plug In Cart. It has balloon tires which makes it roll real nice on sand. The only drawback to the cart is at the end of the day I have to unload most of my crap out of the kayak, roll the kayak on its side, and plug the cart into the scupper holes. There are some hacks out there using bungee cords to put the cart into the scuppers without rolling the kayak over but I was not interested in taking that route. When I use this cart I can strap it to the kayak after launch. No need to return it to my truck. This comes in handy when launching a great distance from my truck. It is a nice cart for the PA 14.
I also have a Wilderness System cart and started experimenting with that. I have used it three times in the last two weeks and it appears to work for me. There are two draw backs: one, I have to lift the rear of the kayak up and put the cart under it, then strap the kayak onto the cart or it will eventually slide out as I roll it (I may not have it fully adjusted yet to fit into the grooves of the hull). The second is that after launch I have to return the cart to my truck in that it is pretty big and would be difficult to attach to the kayak after launch.
I think the C-Tug identified by Dr SteelheadCatcher is one a lot of salt fisherman use. I may be mistaken but I think it can be disassembled and stored in the front hatch of the kayak after launch so it is available on return.
Some of the carts take a little more work to use and all seem to have pro's and con's. Some people go out light and rolling the kayak on the side to put the cart into the scupper holes is no problem. I seem to go heavy when I fish (I take coffee, water, lunch, kitchen sink, you know...).
If I had a small satellite TV to watch games on the lake I would probably take that too.
The balloon tires on the Trax 2-30 do rock when rolling on sand though.
Good luck! He will love the PA!