Hey, Lawrence! A road trip means a tour, that a group (normally) or someone starts, sleeps in different places or cities during some time, and then comes back home. In this case, a working road trip can be a tour like this, with the main purpose of develop something. Like Rue said right above, it's not a vacation trip, they could be geologists studying special situations of every place, or any other kind of job. I hope this helps! :)

I don't have enough context to know for sure, but it almost certainly means they're working as they travel rather than purely vacationing (maybe they're geologists studying rocks around the country, or perhaps they work online).