Mark finished in a B&B maybe (8)
I believe the answer is:
stopover
'a bb maybe' is the definition.
(you might stop over in a bed and breakfast)
'mark finished' is the wordplay.
'mark' becomes 'stop' (stop is a kind of mark).
'finished' becomes 'over' (similar in meaning).
'stop'+'over'='STOPOVER'
'in' is the link.
(Other definitions for stopover that I've seen before include "Break in a journey" , "bed and breakfast?" , "that hotel can provide?" , "Overnight stay" , "Stay (of just one night?)" .)