I would agree with all of the above.

Like everywhere there are great and not so great areas. Stick with their oppos and don't take too much advantage of the local booze......and don't touch whisky.

If on the hills, depending on their experience, keep to the paths and let others know where they're going and their approximate return time. Wear clothing appropriate to the conditions

In the cities, keep to the city centres and well trodden paths.
They will enjoy it and I hope it will be a great holiday with positive lifetime memories

Finally they need to remember when crossing roads, we drive on the wrong side of the road, so the vehicles will be coming from the other way