We did it the other way round as we were in portinax in May.......can't remember how much it was but it wouldn't have been too much ( Or we wouldn't have gone on it !! )

It takes about 3/4 hours and it's a return trip. If I remember rightly that trip was twice a week once in the morning Tues( about 10 ) and once in the afternoon Thurs( about 4 ) it did go on other days to different places.

I would recommend you get there a bit early as the train fills up very quickly.. you get a guide and it's a nice way to spend a few hours.

BB