Startups are very demanding on time and attention resources. Families with children would feel the strain of absent parents. It could work out in some cases but for the general case it’s not the best idea.
If you have to travel, take a couple days before/after and bring your family; see the city. Even ask whomever you’re meeting where to go. More often than not, you’ll spend some time with them because people want to show off their city, which just makes it that much easier to sell when it comes time to do so.
...
Okay seriously this can work but it will really force you to work on your communication skills. Which is probably a good thing anyway, for both the business and the relationship, but it's very challenging.