We arrive late evening at Heathrow, pick up a rental car, and need a recommended hotel/B&B along the M40, perhaps in Slough or High Wycombe. We hope to avoid airport noise and congestion but don't want to drive all the way to the Oxford area. Any suggestions on a nice, clean room that's not too expensive?
Windsor would be a great place to stay it's a 15 minute drive from Heathrow.....Ye Harte & Garter Hotel..Castle Hotel...have stayed at both and both are very nice. Ye Harte & Garter is across the street from Windsor Castle and the Castle Hotel is a block down from the castle.
Especially as you are are arriving late you may well enjoy the very convenient Holiday Inn on the roundabout of the M40 and the A404 at High Wycombe.
Have a look at the website and book early for discounts.
There's a Marriott in Slough, but have you seen Slough? By the way, Slough is on the M4, not the M40.
We've been pretty successful in the hotels in the immediate vicinity of Heathrow especially the Crowne Plaza.