Personally I describe things from my own travels that I have noticed in the background while on the move. For instance animal spoor, tracks, scats, some interesting piece of floral or wildlife. Bits of debris or trash which would give some indication of what is occurring in the local area. I mix up waymarkers or while on the march the party expects to find milestones at certain points, but those are missing or destroyed. I confuse the trial or road they follow.
Also I leave clues which might indicate local population types or even that NPCs they might be familiar with have passed the way ahead of them. Then again you can leave other clues as well, such as signs of plague, fire, earthquake, disaster, heavy trade, caravan ambush, raider army, etc.
You don't have to have your party engage any of these things directly to create a lot of tension about what they might encounter, what the clues they discover might or might not mean, or to misdirect or confuse your players.
I run a setting set in the Byzantine empire circa 800 AD, so there are always signs or evidence of barbarian border raiders (like the Goths), Arab or Persian scout infiltrations, populations on the move, wildfires, plaques, earthquakes, famines, border skirmishes, troop movements (as a matter of fact my main party is a special agent team for the Empire), monks and hermits in travel or on pilgrimage, food transport, merchant and trade shipments, pirate and brigand raids along the coastal roads, dogs which wanna take up with the party, abandoned horses, wild animals, and even the occasional monster rumor and strange track and scat evidence, that kind of thing.
Just imagine what real life would be like in your own setting, how people would move, what would be happening along any given route as it relates to the area encountered, traveled, or the destination path, and there you have it. Storms are good too, especially fierce ones along to coast and early or late season heavy snowfall, torrential flood, etc. Roadside travel is a very good way to allow the party to resolve moral dilemmas, something I include in every game. For instance recently the abbot of the Monastery of Studios asked the party to accompany his niece to Gallipolis from Constantinople. Along the way on orders from the emperor they investigated a disturbance in small village where they were ambushed by Goth raiders and the girl abducted either for ransom or to be sold into slavery. The party was also supposed to go on to Gallipolis to meet an embassy from the court of Charlemagne to escort them back to Constantinople. After the abduction the party was faced with; 1. chase down the Goths and try to recover the kidnapped girl before she was sold, ransomed, raped, or killed, or 2. proceed on to their original mission and meet the envoy from the Franks to escort them back to the Emperor. Once they made their choice (follow their orders as quickly as possible then form up a raider scout team to hunt down the girl after the envoys were delivered) I still placed numerous obstacles align the roads to slow them down and thwart their intent. Meaning you can always turn travel into a aspect of a mission or adventure. That is travel can incorporate mission objectives or hinder them.
Anyways I made up lists to not monsters to encounter on travel, but also events and evidences and clues and obstacles to encounter. things such as plague zones, rockslides on roads, pirate attacks, skirmish areas, earthquakes, wildfires, drought areas, violent storm encounters, raider bands, enemy scouts, and so forth and so on.
Use things like that instead of just monster encounters and everything or anything can become an interesting aspect of travel. Hope that helped.