Can you/ should you use the same walk for every exercise?
That depends how much you practice. If you do one exercise per day, then it is most probably ok to have the same Journey again and again.
(Note: you might cleanse it before you start. Watch this idea, it is an interesting one. If – in order to remember – you make it unusual and extra-ordinary – then to create the opposite effect, you have to do the opposite: make it boring and uninteresting. This means: go through your journey stage by stage and drain it of every element of life and livliness. Drain the colours, there are no sounds, no emotions, and no movement. A bit like a ghost sitting-room (in this case). And after this wiping clean THEN you start to connect ‘unusual-ness’ to each stage again.)
I have met students who survived college life with this one journey alone. They said: there is no lecturer asking for more than 10 answers to any question. So in a kind of startrek parallel universes they have the sitting-room journey ‘parallel’ in their head.
My opinion: if it works for you: fine.
My advice: more journeys simply make remembering so much easier. (see hints and tips below)