Ideas for one night away somewhere green next week

[Poseidensgrumpyneighbour]

So I unexpectedly have 48 hours on my own with DD15 Mon-Tue next week. I’d love to book a night away with her somewhere that we can get to easily (ideally on train) - just somewhere we can go for a nice walk, get a pub meal etc dog friendly would be ideal but not essential. Anyone have any ideas? We live in N London. Thanks I’m advance.

Brighton or is that not green enough? There's a direct Thameslink train from St Pancras.