I have travelled extensively with a ETRS with 75, 40 and 150mm lenses. Takes a lot less room than many 35mm outfits...

Nowadays I'm more likely to bring along a 9x12cm Voigtländer Bergheil, with a MF folder (Zeiss or Voigtländer) as "backup". The backup is necessary because I only have four film holders for the Bergheil...