You can park near the exit of the A50 to the Sonseweg. Next to the scouting is a large parking place. It is halfway through the trail and is a good place to ride from to access the Green Trail
of AquaBest - Green and Red Trail
if you want to make the trail slightly longer.
This is the official connection trail between the Purple Trail of the Vresselse Bos
and the Green Trail
of AquaBest. The official trail goes alongside a large road and then through SON. This is the least interesting part. After the tunnel, it heads under the A50 and it gets more interesting, especially after crossing also the Sonseweg. The path can be followed in both directions.
As an alternative, when you reach Son, you may want to consider taking the Bijenlaan and then before crossing the A50, going left in the direction of the Alpenlaan. I haven't done that part myself yet, so I'm not sure if this is better.
Warning if you take this alternative road: there are no MTB signs until you get back on the official trail.