Location, location, location. As you will discover, the accommodation options near Sandwich are somewhat limited. The Yarrow is an ideal base for your stay during The Open. Its 7 miles by car which will take 20 minutes or less.
Between 1837 and 1851, Charles Dickens spent his summers in Broadstairs and there is a museum which is worth checking out.
From a golfing perspective you are within range of some great golf courses which can be played during The Open including Royal Cinque Port (Deal) & Princes Golf Club - Both are a fine test of links golf.
One of the very few hotels with air conditioning. Temperatures can get very hot mid July so this is a key benefit of staying here.