There are also "labour exchange" possibilities. You work for someone for a fixed time ( from a week to a whole season) and in exchange get accommodation ( in your case say a pitch with EHU and water) I can't remember site names at the moment but I'll have a look online. Work varies from house and garden maintenance to small holdings to harvesting.
It's British .. hope you are handy with a tool box and gaffer tape..
Payload will be influenced by the nose weight from the trailer but probably not by more than 50kg. But the trailer might nudge you towards the gross train weight.
I think towing a box type trailer is probably your best bet..
Good luck and have fun.. Head for the sun !!!