Hi folks, looking for guidance on transportation from London to Canterbury.  Rick's guidebook notes the options, so I had planned to go from London to Canterbury by train (from St Pancras or Victoria station).  A few months ago I naively thought this would be straightforward.  Now I realize that all sorts of horrors in the form of strikes and delays may await when I arrive early Sept.
I would appreciate input on the following questions (and anything else I need to consider).
---St Pancras vs Victoria, to Canterbuy,  take the shortest option or are there other factors to consider?  What happens if I buy the ticket in advance and then a strike is called, do I get a refund?  How much advance notice would I have? 
---And the back up plan would be bus from Victoria Coach station?  Would all bus options be sold out in the event of a rail strike?
---Once I settle on that plan, I need to sort out how to get from Heathrow to St Pancras or Victoria.  Take the Tube?  In the event of a strike, would a bus be available?  
It's a bit daunting.  Thank you for intel!
Suzanne