OK, disposing of travel trailer

If it wasn't so far away, I would gladly take it off your hands.
I would strip it down to the frame, sell the metal for scrap, take the rest to the landfill, put a deck on the frame to make a flatbed trailer out of it, put good used LT tires on it, then either sell it for $500 or keep it for personal use.
I can get a new title for it here, along with a new VIN, and sell it as a 2013 homebuilt trailer.
But, it is too far away.

Last time I checked, the local metal recycler was paying 10 cents per pound for steel so the frame might be worth a few dollars.

In Central TX, freecycle or Craigslist will get rid of it fast. There is always someone else who might need some type of enclosed storage on their property, or at the least, they will torch it, cut the pieces up, and sell it for scrap.

Donate it for tax write off?

Around where I live, there are some junk yards that will give you $100 and haul away your broken down car. They use the old thing for recycling parts. Some body shops around here (at least they use to) and definately, back-yard do-it-yourselfers use these "salvage" yards for parts. Some are designed so you go out to the vehicle, take the part off a junked car, and then pay at the desk for your part, usually very cheap. So, they do make their $100 back pretty easy.

I've seen a couple not "that" far from where I live that have some old trashed out campers and Truck Campers in their stock pile. Perhaps you have such a "salvage" yard in your area that will give you something and haul the old trailer away for you.

Yes, I would check with the local landfill and see if they will take it and what the cost would be

I hauled an old 26' cabin cruiser to the dump. I wanted to keep the trailer for another boat. The dump folks hooked on to the back of the boat with chains, pulled it off the trailer, then crushed it by driving the big earth mover over the boat. It just exploded! The driver said to keep bringing the old boats in, he enjoys running over them.

Everybody, awesome!

Try your local FreeCycle if you're giving it away - someone will be interested for whatever reason.

Cheers,
xena

Auto scrap yard? We have a place near us that takes junk RV's cars & Tractors and strips them down. They use the metal to make Rebar.