I'd say 'normal' is to route over Oxford city. In fact one of the IFR arrivals is almost due north from CPT (353R as I remember, but don't take my word for it!) which takes you that way anyway. Watch out for the Benson MATZ, though, and the area to the west of Benson, both of which are busy with Tutors on AEF and UAS sorties (doing aeros and formation, for example) - this is the area there was a fatal mid-air last year - and they are active at the weekends, too. Compton is a major honeypot - avoid 'obvious' levels like 2000 or 2500. Also, Abingdon airfield is emphatically NOT disused and at the weekends is active with Vigilant motorgliders, mostly in the circuit but also to the south and west doing general handling.
If you do route via Brize you avoid much of the above; if the weather is suitable you could go >3500ft to avoid the CAS and then descend between the Charlbury VRP and Kidlington; but it's not necessary; the above route is fine as long as you keep your eyes peeled.
Tim