For directions I defer to Trill's own tried and tested directions:
https://www.trillfarm.co.uk/pages/contact-us

Once you arrive at Trill there will usually be someone around to meet you and direct you to the parking. From there it is a five minute walk to the campsite.  Usually we can use the Landrover and trailer to take peoples stuff up the hill in small batches, while people walk up.