1 VHF com is needed for general communication in Area/s so I think the other should monitor 121.5
My 2 cents FWIW:
- Com 1: FIA, Class E or whatever frequency communicating with/listening to ATC on;
- Com 2: switched between CTAFs approaching or in the vicinity thereof, other times sits on 126.7
Thus theoretically the "whole" traffic picture is obtained.