In D&D 5e, the daily rate of mounted overland travel is generally the same as on foot, because horses get tired and adventurers carry a lot of heavy equipment.
See the section Special Travel Pace in the DMG (p. 242–243). This section starts:
The rules on travel pace in the Player’s Handbook assume that a group of travelers adopts a pace that, over time, is unaffected by the individual members’ walking speeds. The difference between walking speeds can be significant during combat, but during an overland journey, the difference vanishes as travelers pause to catch their breath, the faster ones wait for the slower ones, and one traveler’s quickness is matched by another traveler’s endurance.
In the same section, the rule is:
- In 1 hour, you can move a number of miles equal to your speed divided by 10.
and then:
- For a fast pace, increase the rate of travel by one-third.
- For a slow pace, multiply the rate by two-thirds.
So an unencumbered horse with a speed of 60 could theoretically travel 6 miles in an hour at a normal pace. At a fast pace (a gallop), 8 miles per hour. That's "twice the usual distance for a fast pace", where "usual" means a creature with a speed of 30. This suggests that a riding horse with no rider, traveling alone, can cover 48 miles per day at a normal pace.
So the rule that "a mounted character can ride at a gallop for about an hour, covering twice the usual distance for a fast pace" seems to exist to allow for mounted travelers covering short distances quickly by using the mount's speed instead of "the usual pace", for up to an hour each day.
So, according to the rules, a traveler on a horse at a normal pace (3 miles per hour) will cover about 24 miles in an 8-hour day. If you make the horse gallop for an hour each day (fast pace for a horse being 8 miles per hour), that range increases to 29 miles. That's within the realm of what you would expect in real life, with a fast horse on good roads in fair weather.
Variant: Encumbrance
If you're using the encumbrance rule, a Riding Horse needs to be carrying less than 80 lbs of rider and equipment to get its full speed of 60. Loaded with between 80 and 160 lbs it has a speed of 50, and carrying between 160 and 480 lbs (its maximum carrying capacity) it has a speed of 30. A 200 lb adventurer in chainmail with a dungeoneering pack, longsword, and shield weighs in at about 325 lbs, so under this rule a horse's travel pace is usually the same as an unencumbered adventurer on foot.
It does not apply to combat.
The Elk Aspect specifically states "Travel Pace" (PHB. Pg. 182) not movement speed. This feature was intended to allow the party to travel quickly not perform swifter movements or actions during combat or other instances.
Also, if you refer to the activities you are able to perform while traveling (PHB Pg. 182) there is no such mention of combat, as you cannot perform combat while traveling, as this would cease traveling and initiate combat, in which case would cease the Elk Aspect of the Beast as you are no longer traveling.
Best Answer
No - but some things can change it under specific terms
Travel Pace generalizes the time it takes to go a distance when travelling:
At this point, the faster speeds aren't creature dependent, but dependent on how aware you want to be of your surroundings as you travel.
Mounts and Vehicles provide a faster, but short term option
It suggests that mounts can help increase your travel speed, but only for about an hour without needing to exchange your mount for a fresh one.
Combined, it seems there is some leeway here, but overall, travel pace is travel pace regardless of base speeds.
This is further substantiated in the DMG on page 242 (Thanks sdjz!)
If you continue, there are additional boosts to travel pace if a creature is: