If it is possible to have a man with you, this will be much better, but this is not a must. The Khulwah (being alone with a member of the opposite sex) could be avoided just by having another woman or man, along with having no cause for suspicion, since it is not possible to always have a Mahram (spouse or unmarriageable relative) available.
A woman should not travel except with a DhuMahram (spouse or unmarriageable relative).