I think "in comfort, comfortably" are best suitable for 편히.
She is walking in comfort/comfortably.
그녀는 편히 걷고 있다.
She is talking on the phone in comfort/comfortably.
그녀는 편히 전화로 통화하고 있다.
She lives in comfort/comfortably.
그녀는 편히 산다.
I hopr it helps you.