Hey there, you can pretty much just pick any part of the river and take a nice walk along it, take a look on google maps! It runs right through the the city so in the city parking would need to be paid for, my favourite parts of the river are in Hagley Park where there is some free parking! There's some nice walks along the Avon in the red zone too where you can park in lots of places along the street! It runs all the way from Mona Vale(also a nice spot)to Brighton!