I think Traveler's boots are only for the "Man" race, as I have never been able to fit any other race with them.
It's one of things you have to "guess" at.
Don't have to guess, it's all in the XML files.
The Traveling boots are restricted by the following tags
<SupportedUnitModelType>KingdomMale</SupportedUnitModelType>
<SupportedUnitModelType>KingdomFemale</SupportedUnitModelType>
Several of the Core Accessories are limited in this way. And due to the way the default peasant designs are setup (Kingdom of Men), this further complicates matters.
Especially for a race like the Tarthans, their clothing/accessory options are even more messed up beyond these boots.
See this thread, and this.
The issues doesn't stop there since Stardock included several items in the default shop store.
Take a kingdom level 1 city for reference.
<!-- Item Shop - Base Items -->
<UnlocksShopItem>SaltedPork</UnlocksShopItem>
<UnlocksShopItem>GnarledClub</UnlocksShopItem>
<UnlocksShopItem>Staff</UnlocksShopItem>
<UnlocksShopItem>TravelingBoots</UnlocksShopItem>
<UnlocksShopItem>Recruiting_Shirt</UnlocksShopItem>
And a fallen level 1
<UnlocksShopItem>SaltedPork</UnlocksShopItem>
<UnlocksShopItem>GnarledClub</UnlocksShopItem>
<UnlocksShopItem>Staff</UnlocksShopItem>
Ex. What do the other races get that men don't get, to make up for the lack of traveller's boots and traveller's cloak?
Hah, nothing.