From my experience in town, here is a map of places that are safe (and unsafe) for Segway gliding.
This is a work in progress and as I try out different routes I'll be updating the map.

• The old industrial area is very dangerous, no sidewalks, no shoulder
• Do not go up Hualalai road past Kaiser Clinic
• Do not go up Kuakini Hwy past University of The Nations
• Still trying to figure out the safest way to get to Kmart/Macy's/Makalapua theatres, there are no crosswalks or sidewalks for both entrances