Travel inside Japan, for an authorized person going to someplace on the beaten path-- remarkably easy, for the level of technology. Travel outside of Japan, or for someone of a class that didn't have the means to travel? Much, much harder; potentially illegal and impossible -the Tokugawa's sakoku ("closed country") policy largely forbade Japanese from traveling abroad, and permitted only very restricted travel by foreigners to trading ports. Within Japan, there were complex systems of permits and barriers (called sekisho ( 関所 ); if you were authorized to travel, things would have been pretty easy, considering. If you weren't so authorized, very difficult.

The Bakufu established well policed roads with way stations, coaching inns and travel along these roads was about as good as could be achieved at this pre-Industrial level of technology. These post stations were under the supervision and inspection of the central government; they were efficient and safe. Fear of robbery was low -but not absent-- and people traveled for recreation as well as business or political purposes.

We've got lots of travelogues and artwork, describing and illustrating famous routes. Perhaps the most celebrated would be Hiroshige's famous Fifty-Three Stations of the Tōkaidō Road; Hiroshige made these prints in 1832 after having traveled from Edo (modern Tokyo) to Kyoto. The Tokaido was the most important of the "Five Roads" established in the early 17th century.

Now if you'll look at a map, you'll see that these routes cover only an area in central Honshu, a bit more than the Kanto plain, but not that much more. A traveler heading further, say to Sendai, would have a harder time. Japan had coastal sea transport, and established maritime communications corridors like the "Inland Sea Route", but Japan is a mountainous country and there were plenty of places that were hard to get to . . . it's got plenty of isolated valleys and out of the way islands that are hard to get to even today; the Iya valley on Shikoku was famously a place that folks on the run escaped to, including perhaps the defeated Taira clan (of Heike Monogatari fame)

See:

Breaking Barriers: Travel and the State in Early Modern Japan -- most detailed look at this specific issue in English.

Excursions in Identity: Travel and the Intersection of Place, Gender, and Status in Edo Japan -- a look at how travel depended on who you were and how you were placed

The System of Communications at the Time of the Meiji Restoration [1941]

note the date here, this is an essay by Baron Mitsui that was published on the eve of Pearl Harbor; more historiographically useful than comprehensive, it gives you a good idea of how mid-century Japanese understood late Tokugawa communications.

Tōkaidōchū Hizakurige in English known as "Shank's Mare" -- comic travelogue novel of two travelers on the Tokaido, written between 1800 and 1820. If you're looking for the "Tokugawa Road Trip" -- this is it.