Gotta disagree with most of the above. Fair enough, if we get 5 weeks down the line and Easter is Baltic then fair enough. But to discount it now is just stoopid.
Best bet with a wean is to go up the hill on the first fire road instead of the usual ‘singletrack’ . Basically go to the upper car park and keep going up up and up. Keep left at the one junction. You’ll see people in the trees on your left for about 2 miles and then the trail pops in from the left and off you go over nessie bumps.
We used the trailer up to that point when they were very small (4yo) , then at some point swapped to a tow rope. The tow rope is not a good idea on the single track ascent due to the bends and huge numbers of people you’ll overtake😎. But on the fire road it’s ideal.
If you arrive late at easter then you may even find the top car park is full and they’re using the forest road as overflow, which gives you carte Blanche to drive up most of the first hill anyway👹
The blue from there should be pretty ok for a 5 yo.