I have never heard the term "roadbook" either, but it sounds like a detailed route plan, such as generated by mapping programs like Mappoint or even Google Maps. I had many of these type of programs in the UK, but in Thailand only have the maps which work on the GPS and not on the PC.
The GPS gives you a route of course but it is difficult to view complete on the GPS, but one can download to the PC and view there, but it is clumsy.
If anyone has good Thai maps that can be used on the PC and used to generate routes, and record tracks I wuld be interested.
At the moment I use Thinknet PC map to plan and to print selections to take with me on the road. I import small areas into a shareware program called Oziexplorer, I calibrate these and can then use Oziexplorer to recod tracks from the GPS and also to plan routes and feed back to the GPS, the painful bit is the map calibration and one can only do an area of say 100 km by 100km if one wants to retain sufficient detail.
Any better ideas for route planning on the PC that can be fed back to the GPS automatically.