Ultraviolet Grasslands has some good ideas for travel-as-exploration (
free version here). I just got it, have not yet played it, but it looks interesting. First of all, it's a pointcrawl instead of a hexcrawl. This is important because you can hand the players a map and there are discrete locations they can visit, which might do a better job at generating exploration than the 'wandering about in the wilderness' feel of a hexcrawl. Each location is a mini-hub for other smaller locations (dungeons, etc). Second, it zooms out the travel, where you have a caravan that can carry a certain amount of supplies, the caravan has its own sheet, and you can upgrade it and add followers (this part is inspired by the oregon trail videogame). This means that resource tracking doesn't happen at the individual character level, but at the group level, and is abstracted. Third, it provides things to find other than dungeons, including trade goods, and so you can set up trading routes. Or, you can explore all the way from one end of the map to the other, with things getting weirder the further you go.
I think for exploration in dnd, either at the wilderness travel scale or the dungeon scale is a good procedure, a set of things to do each x amount of time, with resources to check off along the way. It's a sort of strategy mini-game in the same way that combat is a tactics mini-game. These
structures are
notably absent from the current edition (yes I've read the train wreck that is the 5e dmg).