All are grammatically correct.
#s 1 and 3 are probably most likely to be used in normal speech.
#s 2 and 4 are slightly awkward even though they're grammatically fine.
1. It was great fun last weekend for you to visit our nursing home.
2. Your visiting our nursing home was great fun last weekend.
3. The visit was great fun last weekend.
4. Visiting our nursing home was great fun last weekend.
(Are they all grammatical and interchangeable? Or which ones are acceptable grammatically?)
2 answers
they are all grammatcal and interchangeable. 1 $ 2 the best