Check that they area you would like is not already mapped @ http://gvoc.whyjustrun.ca/maps/
If decent aerial images are available (e.g. recent Google Maps data) it would typically require 2 hours drafting to set up the base-map. Fieldwork for most areas will require 3-4 hours work, probably spread over two visits to the school, and drafting for the final map requires a similar amount of time (3-4 hours). If the school is a considerable drive from home base, transportation has to be factored in. As a guide, most maps cost $200-300, depending on the size and complexity of the area being mapped. A more detailed quote can be provided once the area to be mapped has been defined.
Open park is easier and takes less time then detailed forest.
Orienteering Association of British Columbia may be able to assist with costs. Please see check-box in form.