Wandering and strolling by river (8)
I believe the answer is:
rambling
'wandering' is the definition.
(I know that wandering can be written as rambling)
'strolling by river' is the wordplay.
'strolling' becomes 'ambling' (I've seen this before).
'by' means one lot of letters go next to another.
'river' becomes 'r' (abbreviation for river).
'ambling' after 'r' is 'RAMBLING'.
'and' is the link.
(Other definitions for rambling that I've seen before include "Roaming" , "Walking about or talking aimlessly" , "Confused; walking for pleasure" , "Taking stroll; not keeping to point" , "Discursive" .)