I needed a heftier TT Safety Chain, so I got 9' of 'peened' high strength, 2,600 lb.-rated Chain and 2 'Hockey Puck'-shaped Locks keyed alike at Home Depot for ~$66- total. That included 2 substantial Safety Hooks w/spring clips that keep them retained on the Hitch Receiver. These Locks are 'satin' finish and have a plastic Key cover. Single or keyed-alike Locks have the Key Code on the packaging, so you can buy identical Key Locks.
I loop the Chain in-and-out of the Tongue front symmetrically, and keep it immobile by a threaded, closeable Link. Both ends then drape to the TT Receiver Loops. On site, I can remove this Chain and loop it through a Wheel to the TT Frame and lock it. Wheel and Spare Tire Wheel Locks complete the the installation which can only slow down Bad Guys; not prevent theft by the determined/well-equipped.
An Alarm, when I'm off Hiking while Bookdocking, didn't have much appeal to me.
MasterLock Discus