I went past last night. There’s a 5m long section of pavement, with low kerbs either side, that takes you past the roadworks. Almost never any pedestrians there so you probably won’t need to dismount. I passed about 10 cyclists coming the other way along the closed road so it’s being well used. Enjoy it while it lasts.
I’ve been going that way every day and it seems fine to get through along the pavement. I had to get off and walk the bike through part of it this morning to get around the workmen and lorries, but they were quite polite about moving out of the way. Its nice and quiet along the rest of the road from Didcot and through the village 🙂