Generally I find any travel planning type website to be a real pain. Clunky, slow to use, and not at all easy to use on a widescreen monitor, never mind a phone.
However, there’s a new feature on the National Rail Enquiries website that I really like. You can very very easily generate a PDF timetable of any custom journey. It’s only of limited hours, but if you regularly do a journey it’s great. e.g. 8 til 11 and return 5 til 8. on any route, on weekdays, or weekends or both. The resulting PDF is fairly light and esily viewable on any phone capable of viewing a PDF. Well useful.