Hi VT,
I havent flown on mainland UK so i cant imagine how busy it is,, in fact it would probably scare me!!m the reason is that flying around my area is so unrestricted its unbelievable. Once your clear of the Belfast TMA you can fly wherever you like, There are no specific VFR routes that im aware of.
Landing fees i believe are around £15, ive never had to pay them though being a member of the club.
there are 2 runways at the field, the tower will usually clear you direct having left belfast TMA to the field to join either straight in or left/right base depending on runway or you can potter along the noth coast (definately advisable) and enjoy the view
hope this helps