There is an argument that it is better to point the service at Canterbury than Folkestone and Dover as even if the population of Canterbury is less, the tourist / student demand is greater. Redhill to Canterbury might just about be possible in an hour with stops only at Tonbridge and Ashford but the trains would almost certainly be practically empty most of the time, even without the current issues.
I would catch it between Ashford and Tonbridge, just for the fast run on the centre roads.
Very rare now days, but they did it one sunday during engineering works on HS1 a couple of years ago. I timed it taking 23 minutes between Ashford and Tonbridge !