From a sandbox OSR referee perspective:

In the “pull you”-section, the modules are parts of the setting. As you know, they are not prepared stories. The emergent events are the interesting part, and a good module will facilitate interesting and unexpected events and narratives. The unexpectedness is part of the promise; otherwise, why bother running the things when you already know what is going to happen?

If you are not playing to find out, the module is boring. It sounds like this is the case with the game you are using.

“I have to think there’s a central tension to Forbidden Lands that’s almost certainly the same tension in lots of hexcrawl-y sandbox-y trad-slash-old-school games, yeah? You do all this procedural creation on the fly for journeys via tables or oracles or card draws, whatever, but that’s just kind of filler until you get to the carefully crafted adventure site where, one supposes, the “real” game lies.”

No, certainly not. Your game procedures are built to create interesting content. If the travel is inconsequential and boring, you skip it (by handwavery or rulings). But when running a sandbox game, what happens on the road is definitely interesting; otherwise you would be running a point-crawl.
If the stuff is not interesting and create exciting emergent outcomes, your travel and random encounter procedures are failing.