Short answer: The Outdoor Notebook Companion is The Notebook Companion with an added chapter dealing with outdoor activities and offences which occur off-highway.
The material in The Notebook Companion deals primarily with offences occurring on our highways and related to vehicles. Most off-road subjects have been removed to concentrate on offences occurring on the highway, since urban and municipal police do not need these other sections. O.P.P. officers, Ministry of Natural Resources enforcement officers and other officers in rural and/or northern areas do deal with hunting, fishing, snowmobiling, all-terrain vehicles, etc. Therefore, The Outdoor Notebook Companion has all the material that The Notebook Companion has, with an additional chapter consisting of 16 pages with the outdoor material.