On a perfect sunny day all you need is a destination…
and Sissinghurst Castle and Gardens and Scotney Castle, both in Kent and practically down the road from each other (about 10 miles)… so easy to visit both on the same day… especially if you start out early enough.
Both destinations are National Trust, if you have membership so much the better, otherwise entrance fees are: Scotney £14.00 and Sissinghurst £11.
I suggest you check opening times and days because these do vary during the year and some days during the week they are closed.
Tip for the day take a picnic lunch and avoid standing in long queues for simple “cuppa tea”, these places get very busy especially on weekends.