In the 60s, when we an established top division side, we did the following tours:
1962 USA and Canada
1965 New Zealand
1966 Latin America
1967 Latin America again.
The 65 tour was done in conjunction with Blackpool against whom we played 12ish times in various NZ cities. United had most wins so took the coveted BOAC Cup.
The Latin American tours saw us play in Mexico, Argentina, Peru, Chile, Paraguay and Bolivia. We beat AC Milan 4-0 in a tournament in Mexico..
In.the 70s we went to Zambia in 72 (winning the also coveted Zambia Airways Trophy) and in 75 Kuwait, NZ again and New Caledonia, which must be the most obscure place we've ever played..