losing chains

The westernmost point in continental Europe is in Portugal, and I've started bringing visiting friends there, usually by bike. It's around a 26-mile total trip, with some significant hills (although through judicious use of train stations, you can make it an overall downhill trip). After a vandalism incident, I'm bikeless, so usually I rent two bikes in Lisbon and then go out with them by train. My friend Ely and I were doing this on Wednesday, and as we were struggling along a short bumpy dirt road leading to an outlook near the westernmost point, her chain snapped. This seemed like a total disaster. While the bike shop had given me a simple toolkit, it didn't include a link tool, and I didn't know any other way to deal with the problem. My first guess was that we would need to take a bus back, assuming they let the bike on, and if not pay an arm and a leg for a taxi. However, I decided to see if the chain could be repaired somehow using my tools. I was rather ineffectually pushing at one of the link axles with an allen wrench when a man from another group approached and offered his help. He had a Leatherman, but, more importantly, had a better idea of how to do these kinds of things. We put the chain on the ground and started hitting the allen wrench with a rock in an effort to pound the axle through. This wasn't successful, so finally he just pounded on the axle directly with the rock until it was flat, and then we eventually managed to get a few direct blows with the allen wrench, creating a depression that allowed us to easily push the axle through. Putting the chain on, we then pounded the axle back in with a rock. I rode the bike carefully the rest of the trip (mostly downhill, fortunately), but when returning it, I noticed that at least one link was stretched, with the hole visibly enlarged. Presumably the already poor condition of the chain wasn't helped by being pounded with a rock. However, it made it. I have a new-found appreciation for the importance of carrying a link tool with me when on long bike rides, since I have no idea how to evaluate chain health.