Stay behind him and sod the strava users :-)
Many families use it and are much more likely to on a sunday, so anyone wanting to race down without the chance of meeting anyone has picked the wrong day IMO
That said, I have just properly read the title and noticed he is only 6 ( dont worry this actually makes it easier), my advice is this.
Shortly after the first section you will ride up a long wide stony track that takes you away from the car park area, to your right the trees have been cut down, this is called black ride. After that is a delightful section for youngsters involving stuff a bit more adventurous than the skills loop called the qualifier. This then comes onto a fire road where you go uphill. Shortly after that you take a left on a flat section that comes back onto Black ride, from there its very easy to turn left and re-do the qualifier..
A map can be found here >> http://www.1sw.org.uk/experience/wp-content/uploads/2011/09/Forest_of_dean_map.pdf
Don’t be tempted to go uphill to do Witches finger as its hard work and has been the scene of many an accident.
The beauty of this little loop is that your never far away from an easy descent back to the centre.