Before I book a time slot to visit Hampton court, how much time should I allow for travel from Green Park station to Hampton court on a weekend in August? And what's the easiest route to get there?
Use the journey planner at https://tfl.gov.uk/ for the best advice.
Broadly speaking, tube from Green Park to Waterloo on the Jubilee line then go upstairs to the main train station where you can catch a train to Hampton Court. I think you can either catch a slower direct train or a faster train and change at Surbiton.
Either way, probably about an hour in total.
At least an hour. You can take the tube which will require a change to a train at Vauxhall.
Hour at a minimum.
Oh yeah, tube to Vauxhall then change to train would be fewer changes.
The change at On the train is just across a platform. I’d take train from Waterloo.