Brassneck yeah I ride Swinley daily (it’s my commute). Often take my daughter on tag along (she is 4.5)…main car park is 4 quid for the day (I think – never used it) and puts you right by the start.
Blue and green start from the same bit…. Just head down the end of the car park (if you want to get really close, as you come into lookout car park follow one way round till you see the overflow car park, head down the end by the pay machine and you will be 10 meters from the start of trails.
Red picks off the blue half way round.
I would suggest starting off with a couple of loops of green (which is really short – think I get round in about 5 mins with my daughter in tow).
Plenty of fire roads to pick up and follow, head over Crowthorne way and pick any fun looking trail. Prepare for frequent stops to pick random objects and build tents out of all the old wood.
9 & 6 year old will be fine on all the blue. If you go at weekend it will be very busy in the dry. But just chill and enjoy it…. You will get strava sausages trying to overtake you but just ignore them. Ride at your own pace. The first bit blue especially gets busy before the peel off to red.
Also quite a good playground for the kids and there is a cafe (but food is crap)
Enjoy!