What to do near haggerston castle & berwick upon tweed?

Am going to haggerston castle next week with my wife and 1 year old girl and gran.
Am not sure what there is to do down near haggerston castle and berwick upon tweed for me and my family.
I have been to haggerston castle before but didn’t go out the caravan park at all.
This year i have a car and would love to take my family out the park for day trips and fun things to do but im not sure what there is to do with a small kid and gran.