Especially prominent was 'Iupiter hospitalis' who watched over the 'ius hospitii' analogous to Zeus Xenios (Greek). Mercurius was esp. associated with merchants, and as Iupiter's son, he's often closely associated with Iupiter, as is the case in Ovid's story of Baucus and Philemon in the Metamorphoses, in which the two gods arrive in a village disguised as peasants; the inhabitants don't treat the travelers with proper hospitium in contrast to Baucus and Philemon. The gods destroy the village but grant Baucus and Philemon's touching request. Cf. Acts 14:12 where the townspeople think the itinerant apostles, Barnabus and Paul, are Zeus and Hermes, which in Latin becomes: et vocabant Barnaban Iovem Paulum vero Mercurium quoniam ipse erat dux verbi. Presupposed in the story is the social-spiritual value of xenios / hospitium. On hospitium: http://penelope.uchicago.edu/Thayer/E/Roman/Texts/secondary/SMIGRA*/Hospitium.html
[ iter, itineris , n. ]. Yes; it's the source of English words like "itinerant" and "itinerary." For all forms of the Latin word "journey" or "trip," except the nominative/accusative singular form (used here), you'll see the 'base' itiner- before all the endings: ablative singular itinere (as in "on a journey," in itinere), nominative/accusative plural "journeys" (as in Itinera sunt difficilia , "Journeys are difficult," or Multa itinera facimus , "We make many journeys.").