I will be visiting London in October and would like to take a day trip to Dover. I would like to be able to spend enough time in Dover to tour the WWII historic sites including the tunnels and caves. Any suggestions for tours or how to travel to Dover for the day and visit the sites?
You can get the train from St Pancras or Cannon Street/Charing Cross (depending on what the state of the London Bridge rebuild is when you're here. The journey from St Pancras is more expensive but half an hour quicker. From Dover Priory station it's about a 10 minute walk.
It really is very easy to get there, as mentioned above...
Dover Castle is an English Heritage property. If you google "Dover Castle English Heritage" you'll find their site which will give you information about arriving by public transportation, hours of tours, opening hours, etc. The English Heritage site is full of information.
Dover Castle is one of their more expensive sites. If you plan on visiting a couple more English Heritage sites, consider getting an English Heritage Overseas Visitor Pass. You can purchase the pass at your first site.
We spent a good part of the day at Dover Castle. We arrived when it opened and arranged our tours. We did not have to wait long for our first tour. We were there in July. It was a very interesting day.
Hope you have a good visit.