So I did the travel times as per request. It's just to get a general idea about how large Oedir is, and these times can vary within distance and/or speed. The travel days count nights sleeping, because it's hard to walk on foot or have their horse go nonstop. So 2 days for example counts 1 night, so they would arrive there on the second day. The time travelled can depend on many factors, such as environmental factors or fatigue, so these times may take longer or shorter. There are also many different kinds of environments that are not well suitable for travel, such as the Astricus Desert and Krizala, which may result in fatality if travelled nonstop and may prove to be inhospitable for a horse after a period of time. Some areas are also hard to traverse through, such as the Naihan Mountains which are also difficult for horses. The cities that are secret such as the Hidden City of Mirthal and the City of Stars are difficult to find and most do not know their location, only the inhabitants so travel there may vary as well. I did not include the ocean and islands because the time varies greatly depending if they are a merfolk swimming there or are arriving by boat. Otherwise enjoy!

Oedir:
Cendra City to Aelfmenn Kingdom: by foot: 5 days/horse: 2 days
Cendra City to Niwetri Forest: by foot: 5 days/horse: 2 days
Cendra City to Lledrith School: by foot: 3 days/horse: 2 days
Cendra City to Kingdom of Airen: by foot: 7 days/horse: 5 days
Cendra City to The Gates of the Graveyard: by foot: 5 days/horse: 2 days

Realms of Mir:
Cendra City to Emberi Kingdom: by foot: 7 hours/horse: 2 hours
Cendra City to Fallen City Ruins: by foot: 2 days/horse: 4 hours
Cendra City to Grasslands: by foot: 9 hours/by horse: 3 hours

Sakari Wildes:
Lledrith School to Mere en Watervalle: by foot: 2 days/horse: 7 hours
Mere en Watervalle to Hidden City of Mirthal: by foot: 6 hours/horse: 2 hours
Lledrith School to Duskmire Woods: by foot: by foot: 2 days/horse: 6 hours

Dryhtwood Forest:
Aelfmenn Kingdom to Grand Library: by foot: 1 day/horse: 4 hours
Aelfmenn Kingdom to Hunting Grounds: by foot: 1 day/horse: 4 hours
Aelfmenn Kingdom to Niwetri Forest: by foot: 2 days/horse: 10 hours

Naihan Mountains:
Kingdom of Airen to Qian Caverns: by foot: 6 hours/horse: 1 hour

Krizala:
Islands in the Sky to Jagged Glaciers: by foot: 6 days/horse: 2 days

The Graveyard and Beyond:
The Gates to Undead City: by foot: 3 days/horse: 7 hours
Undead City to Dark Harbor: by foot: 9 hours/horse: 3 hours
Undead City to Dark Canyons: by foot: 2 days/horse: 7 hours

Dangerous Reaches:
Imfala Kingdom to Soiled Plains: by foot: 3 days/horse: 6 hours
Imfala Kingdom to Dragon Breath Springs: by foot: 2 days/horse: 4 hours
Imfala Kingdom to Spring of Immortality: by foot: 8 hours/horse: 2 hours

Astricus Desert:
Realms of Mir to City of the Stars: by foot: 10 hours/horse: 3 hours
Realms of Mir to the Edge of the World: by foot: 5 days/horse: 2 days