Our family really enjoyed the cross training we managed to do on the shore trail at Nimpkish and the BC Hydro River trail in Cumberland. I just want to put in a plug here for:

-Nimpkish lake trail users/builders to improve this once very rough trail which now allows a loop along the roadway to the point and ride back to camp (well, ya did have to hike'n bike a bit but that just makes it a better workout)
-the guys in Cumberland bike shop who provide excellent maps at only $4 each and excellent advice not to try the advanced trails with a younger family http://cvmtb.com/content/cumberlandtrails.aspx use the other map (not shown online) to access the BC Hydro trail system
-BC Hydro for the trail network, parking and marking they provide.

The single track cross country trail "Bear Bait" that you access from the dam at Comox Lake has great swimming, <1km gravel road, great parking. The trail is very well marked and cruising is a lot of fun for the budding mtn biker and just adjacent to a nice walking trail for those not inclined to bike (pls stay off with the bikes), some serious downhill trails with great (and notably not excessively stupid) features The uphill sections were NOT well marked but it is tough to get lost (trails aer well used) tho we almost managed that due to my advanced Alzheimers and ineptitude. A blast and a few bruises were had by most. A great workout finished with jumping from the bridge into the cool Comox lake.

PS: avoid the hideous camping at Comox Lake at all costs dust & diesel, rigs almost touching, 4x4 & ATV, snot nosed kids and adults, gravel beaches dotted with those who should not wear bikinis....you get the picture....blech