This can be more than a little disorientating to a modern reader, at least one who hasn't backpacked, canoed, or ridden any distance themselves. So here are some times and distances.
- A fit person can walk 3-5 miles in an hour. This depends on the terrain. If it's rugged and mountainous, the times can be much slower. (One of my scout leader friends, who is an accomplished backpacker, took two hours to climb 1500 feet in a mile and a half on a poorly marked brush-filled trail not long ago.) People generally don't walk more an average of more than 20 miles in a day. People who aren't routinely hiking may do about 10 miles. There is a group of hardened "trail runners" who are much faster, but they're not typical, and they may average 30-40 miles.
- A horse can ride 20-30 miles without too much distress. If he's pushed hard he can go further, but don't expect the horse to be in good condition after that. Again the terrain matters. A horse that is pushed too hard can die or take weeks to recover. The cavalry killed many mounts by exhaustion. There is a reason the pony express used a set of way stations every 10-15 miles. The rider carried messages as fast as his horses would go, but he didn't ride the whole way on one horse.
- Coaches did something similar to the pony express. The horses would pull the coach for a 'stage' and then the team would be swapped for a fresh one at a 'posting house'. Hence the fast coach would be a 'stage coach'. After 1790 the Bristol to London road had post houses every 8-10 miles and either 'traveling post' or on the mail could get you from Bristol to London in the same day (average 8 mph). It took several decades for the rest of the UK to catch up.
- Road quality matters. 'Tar' Macadam recruited teams of (mostly) Irish laborers during the Regency to 'Macadamize' roads. These were called 'navigators' or 'navies'. If you used these roads, you made good time. Otherwise you might be stuck in the mud or that unique combination of mud and horse droppings called slough. Prior to the Regency and away from major routes, roads were always awful. Something similar happened in the USA, where 'turnpikes' were being made. The high quality roads were usually supported by a toll system.
All this mean that things took time. In one of the books I'm working on "The Mysterious Mr. Willis" a regiment is being organized in 1803 to be deployed in 1805. That may seem a long time, but the 2nd division of the 62nd foot was organized in 1803 in Devizes and deployed to the Channel Islands in 1805.