I live about a mile from there and ride with my 10 year old there pretty often. Hawks Loop is where I would start. I've never ridden Tanglewood, so I can't compare the two. Hawk has a could of pretty good little climbs, but nothing major. The direction of the trails for this year (they rotate) is probably better for for beginners than the other. Hawks has two loops off of it, Norwood and Hicks creek, that you can add for more miles. Hicks is an easy 1 mile loop and Norwood is a pretty easy 2 1/2 or so. I also like Wildlife, but it's a bit of a ride from the parking lot with a smaller kid, we usually just ride from the house so my son doesn't have to make the climb from the parking lot up to wildlife rd.
If you have any more questions just ask. If we were not going to a wakeboard competition t his weekend I'd try to meet up and show you around. The trails are marked very well, so don't worry about getting off track.
Kevin