Dude, as rarely as you're using it to haul the stuff you're mentioning, and as much as it costs, you could buy a cooler and camp chairs for each trip and throw them away on the beach when you leave - and still save money.
Seriously, you don't need a truck for an occasional trip like that. Rent. Use a car-top carrier or a cheap trailer.
UHauls are cheap. A hitch on your car isn't that expensive.
Or buy a cheap trailer like a $300 fold-up trailer from Harbor Freight. I use one quite frequently when I rehab a house for our rental property business. Total cost was somewhere between $800 and $1000. That included buying a hitch and having it installed, buying the trailer, buying lifetime tags for the trailer, buying wood for the trailer bed and sides, and all the nuts, bolts and screws to fasten the wood together. It will last pretty much forever and I'll use it way more than it sounds like you will.
And when we go camping, we take a tent, fire gear, medieval armor and furniture, etc. The trailer works fine for that, too.