A lot depends upon whether you plan to tour with others, or alone.
If it's important to you to bring back pictures that will please you into your old age, and capture the flavour and essence of the location, try to travel alone.
If the trip is primarily to enjoy the company of the local population, your personal comfort and mobility suggests travelling light: a TLR with a wide (50-65mm) lens, loaded with HP5 or TX;
Touring on bicycle or motorcycle, by bus or train : MF/TLR with 50, 80 and 180mm, or (NOT and) 35mm SLR or RF with 24, 50 and 135mm.
Travelling by car: 4X5 with 90, 150 and 360 TP, in addition to the above.
Another personal favourite, maybe as a replacement for a wide-angle lens, is a HorizonT wide-angle camera. Surprisingly efficient, but an acquired taste.
Travelling with a wife: iphone