Abingdon Road is the difficult one because it genuinely isn't wide enough for segregated tracks. But it's also the easy one because there's a parallel, direct backstreet route (Marlborough Road/Wytham Street), and Abingdon Road itself has few enough businesses that it's not really a destination in itself.

The Quickways proposals are focused on East Oxford where there is enough space. Broadly speaking, all of the East Oxford arterials have enough space for a segregated track on at least one side, usually both. It's only the immediate vicinity of the Plain where they're very narrow. But you could get two protected tracks along the Cowley Road as far as Marsh Road, assuming you reworked the road furniture and parking spaces; one protected track along the Iffley Road from the Plain to somewhere round Magdalen Road, and two from there on; two along most of Headington/London Road, Marston Road, and so on.