Suggestions or advice for spending 4 days on the Kent coast Please

Hi there,
I am going to recommend a day trip to Canterbury. I went there for the first time this past December. It's a cute town. The Canterbury Cathedral is why I went. I wanted to see the medieval stained glass. A few nice places for tea too. Several candy/sweet shops.
I went there by train from London, so I am making a guess that there's a train from Dover to Canterbury.

One more suggestion. Hever Castle. https://www.hevercastle.co.uk/
I am not sure how far this is from Dover, but its in Kent. Our kids loved this place. They have jousting events in July. Water garden to play in and lovely gardens to relax in. We traveled via train from London.

Have a wonderful time in the U.K. and on your cruise.

Another big tick for Canterbury. Unfortunately we only had a few hours there as part of White Cliffs of Dover trip. We were there on a Saturday afternoon and had the most amazing experience - sitting in the cathedral listening to the choir performing during evensong. Town had a nice 'feel' to it. Would have loved to spend a day or two there.

You won't get 6 people in a standard taxi, so you may have to make local enquiries as to how best to get around, which your accommodation provider should be able to advise on. Look at Southeastern Trains for local timetables.

Canterbury has already been stated. It's not that close and I think that you could keep yourselves amused closer to home.

There are good walks and cycle paths from Sandgate into Folkestone. I was there one weekend last summer and there was a rowing regatta on the seafront.

One place that is of interest for all ages is the quirky Kent Battle of Britain Museum in Hawkinge, a suburb of Folkestone. It's run by enthusiastic volunteers, who have a wealth of knowledge. They have thousands of exhibits, from uniforms to parts of aircraft destroyed in battle, charting each planes involvement in the war. There is also a small cafe there, which was excellent value. Cameras aren't allowed in and you even have to leave your mobile phone at reception! You need at 2 hours here plus cafe time.

Dover - the town itself is a dump, but the Castle and the National Trust lighthouse and tunnels are worth visiting.

Immediately west of Sandgate is Hythe, a small town that is worth a visit. You can walk or cycle there. The high street has plenty of good cafes and restaurants. It's prettier than Folkestone. There is a heritage railway here, the Romney, Hythe and Dymchurch line that appeals to all ages. The Royal Military Canal runs through the town centre and has a good towpath alongside. It was built to repel Napoleon's forces 200 years ago, but was never put to the test. Nearby is Port Lympne (pronoumced Limm) Reserve, a small safari park where you are taken round in high vehicles.

Thank you all for those great responses! Canterbury was def on our list for sure. I appreciate the comments on local places to visit close to Sandgate. We are leaning towards hiring a driver to get us from the airport and dropping us off at the beach house. Looks like there are rental vehicles that fit 6 available for pick-up in Dover, this will avoid any problems with finding a taxi that fits the whole family.

The best pub in the area (or was at least when I was last there about 2 years ago) is The Coastguard at St Margaret's Bay. You'll need a taxi, but it's a terrific place, great views (it claims to be closer to France than any other pub in the UK), good food and well kept beer.