If "gauntlet" refers to a challenge or trial:
* Ease
* Comfort
* Security
* Safety
* Peace
If "gauntlet" refers to a glove:
* Bare hand
* Ungloved hand
* Mittens (in some contexts)
If "gauntlet" refers to a medieval armored glove:
* Bare hand
* Ungloved hand
* Armored glove (if it's another style of glove)
If "gauntlet" refers to a passage lined with attackers:
* Safe passage
* Unchallenged path
* Free path
* Open road
It's important to consider the specific context to choose the most appropriate antonym.