I have a rescue bengal who is an EG cat. I have taken her on a major multi-state road trip to my folks' remote mountain cabin where even GPS is iffy in places and there is NO hope of cell service. After researching all of my options, I got this:
http://www.com-spec.com/thecatlocator/index.htm
It has a range up to a mile (open land), less in town (couple blocks).
We tried having her out on leash-and-jacket, but she (fortunately for me) HATES the outside. It terrifies her and she runs off pure instinct, hardly even recognizes me (but still, VERY fortunately, has zero aggression - just fear).
She got out at my folks' place. Curious little beast she is. We did not know for two HOURS. When we started looking for her, first within the house with the radio receiver, we could not believe it that the signal kept being strongest pointed at a blank wall! Finally I decided to trust it and went outside, and shined a light in the direction of the signal, called my little beastie's name, and two little green eyes peeped back at me from a brushy spot in tge forest, about 150 yards away. It took a while (she was terrified and did not recognize me at first), but with some calm, gentle talking, and walking near her saying her favorite word (chicken! lol!) she came close enough to touch. I sat a bit, and she "came back down" from her wild terror and let me pick her up, take her inside, and ply her with chicken

She was shaking when I picked her up.
That radio transmitter and receiver is the only reason I still have her, I am certain of it.
While that event was stressful, the roadtrip in general was great, and she seemed unfazed by most of it. She ate normally (voraciously), used her litterbox perfectly (stinky in a Jeep!), and LOVED taking care of my folks' little rodent trouble. All in all, it was less stressful than boarding, and probably equivalent to having a petsitter. For long trips in the future, I'll definitely do the same again.