Today, someone asked AAM about the etiquette of hanging out after work if you're traveling with other coworkers.
For me, the default has always been that we go out for dinner together, at least for the first night. After the first night, someone may be tired from fieldwork or have leftovers. If the field crew is larger (say, more than 4 people), people are more likely to go out and do their own thing, but at the same time, you're more likely to have a Big To Do for dinner at least one night, rather than a quiet meal that ends quickly.
The folks I have worked with have always been reasonable about accommodating dinner. Nobody's taken the only vehicle and left me stranded, and I haven't been bullied into eating somewhere or with someone that I'm uncomfortable with. It helps that I'm a pretty adventurous eater.
At the same time, the expectation has always been that we go out to/meet for dinner, and only that. We're all professional adults, so it's not like the first time we're getting let off the leash (really, making travel into a big party gets old fast), and we have other things we'd like to do in the evening, and so we nearly always separate after dinner.
Of course, there are exceptions. If we have a free day or an especially early day for some reason, I'm definitely up for an adventure. I've visited museums and national monuments, gone to the beach, and played epic games of pool with coworkers. But generally with fieldwork, we all end up exhausted and grumpy at the end of the day.
One of the questions on the AAM post was on coworkers who "run amok" when traveling. Same answer. I have a lovely, civil dinner, and then I go back to the hotel and call my sweetie and zone out to the "storage wars" marathon that's guaranteed to be on. Boring, but then I don't have to try and do physical labor while hungover and my coworkers' antics aren't my responsibility!