I'm fairly certain that I've heard that the Outer Planes have varying travel times, like the Astral and Ethereal do (I think). I think Ripvanwormer said it. So could I get some more information, like what determines these travel times? Sorry if the post isn't very coherent I'm very stressed out right now.
Outer Plane Travel Times
Travel in the Outlands and the Planes of Chaos are 3-18 days between neighboring sites. So, for example, it's 3-18 days between Xaos and Glorium.
In the Planes of Conflict and the Planes of Law, the rules get more complicated; each plane has its own complications, in fact. In Elysium, travel is faster the more good deeds you perform, and if you perform evil deeds you'll never get where you're going; you'll just wander forever through rock and bramble until you practice enough good to make up for your previous evil. In Carceri, treachery speeds your way. In the Gray Waste, you won't get where you're going unless you stop caring if you get there or not. In Baator and Arcadia, there are specific paths you need to travel, and those who deviate from those paths will have more trouble. In Celestia, there are metaphorical paths of virtue that one needs to follow to reach the next layer.
These rules are very vague, and exist only for flavor purposes. PCs should move at the speed of plot, getting where they need to go at the point where travel becomes distracting or overly annoying.
Some sections of the Outer Planes do - but not all of them are very well known for it. Anytime you are traveling within the realm of a deity - the land is divinely morphic, so if the god wants it to take 20 years to travel - it will.
The Hinterlands of the Outlands is very much a perceptual travel area. It may take days or weeks to get out into the Hinterlands, and the terrain is unmappable because it changes on you - but no matter where you are it's about three days back to a gate town. Limbo can be as well. Also the space between the spheres on Carceri, or some of the tunnels in Pandemonium. It's not as common a trait on the lawful planes as far as I know.
The Inner Planes are most known for it actually - the planes are all infinite - but if you keep 'walking' long enough in one direction or another you'll eventually hit the border you're looking to hit, sort of like the plane itself is willing to kick you along to where you need to go if you're consistent enough about it.
That sort of effect can sometimes happen if there is a spot on the Planes that you *know* connects to another spot on a different plane - you can physically walk from one to the other. It takes so much longer than portal walking though that most folks never bother with that.