securing a travel trailer

Pretty much covers it

Take the tires and wheels off.

Too extreme? Boot one or more wheels.

Too extreme still? Coupler lock.

I think that ball lock and the ones that cover the lug nuts would be a fairly decent deterrent. at least they would slow down the theft and cause them to look elsewhere for an easier target.
bumpy

You can get a hitch lock that slides over the TT's tounge or a product from this page to secure your wheels.

Regardless of what you do, if someone really wants it, they just may be able to take it. This happens sometines as forum members have reported stolen TT's from driveways and storage lots. I have never heard of one being stolen from a camp ground.

Make sure you have all possibilities in mind while going over optons to insure it.

Here is a link to a lock made by Reese at Walmart:
http://www.walmart.com/ip/Reese-Towpower-Universal-Coupler-Lock/15125814