Marlow's own station sits a short walk from the High Street. The branch line runs to Maidenhead, where the Elizabeth line takes you straight into Paddington, Bond Street, Tottenham Court Road, Farringdon and Liverpool Street without another change — around an hour from front door to desk, with a seat and a coffee.
Drivers have the M40 at Junction 4 and the M4 at Junctions 8–9, which puts Reading, Slough, Uxbridge and the Thames Valley business parks inside half an hour and Heathrow barely further. For anyone commuting two or three days a week — the pattern most households now run — it is about as workable as the Chilterns get.
It matters for guests, too: the annex's visitors have always arrived easily by train, which is part of why it let so consistently.