When it comes to cleaning things Jimmy beats Mr. Muscle.
We do do a really steep descent to find a locked gate; had to go back up & one very "interesting" section did demand some robust man handling - we had to assist each other as we relayed up; photography is not a priority at times like that.
A mixture of all 3 & it's not well defined which is which.
In general there is no vehicular rights off the public road but it is not exactly tresspassing (fingers crossed)!
Generally you are operating at the tolerance of local landowners & that is a frail tolerance. If you annoy them you will find a locked gate there next day.
A lot of the marginal land is held of commonage & no one owner can lock the others out but they can still lock the gate by agreement.
Apart from all that there are now areas that are specifically conserved where all recreational vehicles are banned - you could have your bike impounded.
In short it is complicated & gives excitement.