Rumlow would totally know who Peggy is! He's read Cap comics as a kid, and he's studied a lot of the history of SHIELD in his time, so he'd instantly recognize her. Likely, he'll accord her with respect for... reasons.

I think a clinic meet-up might be a good place for them? Having patients allows them to not just open fire immediately (she can punch him instead :3)? And maybe she can apply her nursing skills at the same time?