I wouldn´t use "go for a tour". It is not mentioned in the dictionary of collocations.
You can say: do/go on/make/undertake/embark on/set off on a tour.
That sounds quite acceptable to me. I went for a tour around the mountains on my motorbike.
If it's a tour organised by others, I'd use "on" - but that's just my preference.
Does this sound familiar: Five passengers set sail that day for a three hour tour. A three hour tour. The weather started getting rough, the tiny ship was tossed. ...