Tyn y Gongl farm is SE of Plas Uchaf, near where Stad Minnffordd is today. Just follow the road SE from Plas Uchaf and you will find it marked on the old map I provided a link to. Sadly it appears to be under a modern housing estate though I think there are still some older buildings on the corner. (unsure if they are the original dwellings).
If you put your cursor over anything you wish to compare - old and new, you will see it mirrored on both maps, which is handy at times like this so you can find exact locations of streets and buildings.
I think if you look on Google street view you can see the entrance to Plas Uchaf. I haven't checked Tyn y Gongl yet (my computer is playing up

).