Being local, and relocating into central London soon, getting a space in Maidenhead station car park has been roundly laughed at in my company. Other less popular options are Langley (again hard to park – I cycle there from Windsor), and Iver*. I f you have a folding bike in the car, then parking a mile or so from the Elizabeth Line is straightforward. If you want overnight hotels, then there is always Hayes and Harlington and West Drayton. Another option might be near LHR T5, two trains an hour and plenty of hotels that might come with parking. I also cycle there for direct train to Stratford for the velodrome. Travel from INSIDE Zone 6 (last two options) is wholly TFL and hence subsidised.
See what you make of today first. Elizabeth Line is truly excellent. By contrast I travelled on the Overground a week ago and it is showing its age by comparison.
*check Wellesley Road and Syke Ings in Ritchings Park and surrounding roads for resident restrictions. Anything more than 200m from the station is likely to be unrestricted parking as people are lazy!