I have had a couple of questions on the biking opportunities from the site and there are some super tracks just over the road from the caravan field. https://www.forestryengland.uk/wareham-forest/the-sika-trail-wareham-forest
Here is a copy of a pdf you can download from Forestry England showing you in red where Trigon caravan field is in relation to The Sika Trail. If you cycle to the main road and go towards the Birchwood Tourist Park there is a path along side up in to the trail.
Alternatively you can go left up the road for about 1km and turn in after the Wareham Forest Tourist Park.
Trigon Farm Caravan Site 