DWG plan - plotting

i would like to configure the max amount of car spaces to the rear and side of 3 buildings. We would like to be able to use the space by simply surfacing it with gravel and chippings so in the areas where the level differences are considerable ( if there are such areas) it will not be considered a suitable area for parking.

i Have DWG's and would like the spaces marked taking in consideration standard width and circulation. Please bear on mind that we need to cram the absolute maximum possible.