The only sidewalks I recall are on part of the roadway distance between terminals, where I saw some people walking. I assumed they worked for one of the contracting/catering companies in the area. It's the sidewalk on the RHS that has some really colourful plants, after one of the stop lights leaving T1.

That said, [MENTION=412307]CPH-Flyer[/MENTION] had a good question about taking dog on the shuttle.

For anyone else who searches this thread, here is the link to the

NARITA INTERNATIONAL AIRPORT - Transfer Between Terminals

It includes map and info about shuttle services.

https://www.narita-airport.jp/en/access/shuttlebus/

As always, quite informative.