Imo there are nicer places in that part of Sussex/West Kent, unless you specifically need to be on that rail line. Uckfield is nicer imo and has a better range of shops, good library and a lovely independent cinema. And Lewes is nice, but a good bit further out and a bit pricey.
Tunbridge Wells is great for shopping, eating out and has loads of pubs, all of which Crowborough lacks, but TW is a lot bigger (but in Kent, so a grammar school may be a possibility). East Grinstead is smaller than TW, but bigger than Crowborough, good for commuting, shopping and eating out, has a great library, some nice pubs and easy access to countryside.
If you don't mind smaller places, Wadhurst might suit you. The school (Uplands) was very highly regarded 10 years or so ago and still has a good reputation, and there's a station there, possibly on the same line as Crowborough. It's a really nice small market town, with a good community spirit.
I like Frant, too, but can't recall if it has a station, and Tenterden and Biddenden are both nice.