If your sources mean the Victoria Tract, I would say no way. There's not much flat there at all. So, the big question is how old are the kiddies? 5 or 25? The Armstrong Tract which is NE of Arlington is much flatter and more forgiving for the kids. A fairly fit 12-13 year old would be able to handle Victoria Tract. But, younger than that and it will be a long whiny drive home...
Other good kid places are:
Hamlin Park (Yep, there's some trails there.)
St. Ed's
Novelty Hill (Park at the watershed lot.)
Beaver Lake
Lake Sawyer (heading South)
The upper South side of Japanese Gulch
Some of the Towers of Power (Tapeworm area)
The Tuscany development by Ferrel-McWhirter in Redmond has a pretty flat but fun system winding around through it that would be great for the littler kids.
Age and ability is the first question though.