Ministry of forests lists logging roads if your looking to get up into the mountains, these are where I usually head to get my offroad fix. I hear you can also buy very detailed maps from them but have never actually got them myself.
If your looking to get your truck dirty and play in some mud, one place I know of is near my work in the Glenlyon Industrial park in Burnaby. But make sure ya bring someone with you... good chance of gettin stuck! I did.
:biggrin2:
From Vancouver, Head east on Marine, turn right on Glenlyon Pkwy, then left on North Fraser Way... past the buildings there's mud to play in on the left and the right, can't miss it.