I've walked most of it, just the Winchester end to do. Remember the start of this is within Windsor Great Park where you'll most certainly get reprimanded. It used to go through Ascot Racecourse, before renovation, so again a potential problem.
To be honest, I wouldn't bother riding it as there's much nicer trails to ride. For a start you could get a train from Reading to Hungerford, roadie it up to Combe Gibbet then follow the ridge (Wayfarer's Walk) all the way to White Hill, S of Kingsclere.
From here you can be creative and then you can pick up WW bridleway at Dummer to New Alresford. After this it will be mainly footpath.