I'm not a HAM, but have military comm experience. HF, at night, ought to work just fine, as you probably realize. But VHF will be spotty, depending on location. UHF...probably the same as VHF, but with more blind spots.
Maybe someone currently active with a local SAR team can give you some information. Try contacting CLMRG or Inyo SAR; I know they use VHF on the SAR freq, with repeaters on nearby peaks.
