My son and I visited the National Trust property Castle Ward in Northern Ireland. It is the property used to film Game of Thrones “Winterfell.” When we entered the property the person in the guard house asked if we are members of the National Trust. We are not because we live in the USA and do not come to the United Kingdom (includes NI) very often. She gave us a brochure for the Royal Oak Foundation, urging us to consider membership and implying that there are places we could use it in the USA, yet neither of us had ever heard of it. “Royal” in the title is suspicious too!
Essentially, it is a National Trust membership for Americans. It gives the same membership privileges when you are in the UK, but there are no properties in the USA that the membership will gain entrance or that has reciprocal privileges. It still might be a good action to take if you are going to visit a lot of National Trust sites. In Northern Ireland we came across two: Giants Causeway and Castle Ward, so it only makes sense if you are a historical preservation enthusiast.
Post script: We stopped at the Tea Room at Castle Ward and shared a turkey sandwich with stuffing and cranberry. It was Friday, the day after Thanksgiving so it was lovely to partake in “leftovers.”