Fast A roads from Didcot to the A404 near Maidenhead with the only sticking point is the traffic in Henley, though thats mainly through commuting time.
If you're going the opposit way there's sometimes a speed camera van at the top of the dual carriage way out of Henley. It's national speed limit droppin to a 40 for about 1/4 of a mile.
Great loop with mostly flowing curves. Quite heavily wooded between Newbury & Wantage, otherwise pretty open. Best done anti-clockwise.
Nice hill climb up from Wantage over the Ridgway with a couple of open, uphill bends. Thereafter a good mix of straights, bends and scenary