Interesting, perhaps they haven’t released the dates everywhere yet. I’m in New Zealand, you?
The one I’m looking at shows as
"Sun 27 May - Mon 02 Jul
Red Star Special 2018" as a Guaranteed departure for me. When I looked last weekend only the Red Star Special was showing dates for next year none of the tours that do parts of it were showing dates for next year and the available brochure was still the “old” one (my ex-travel agent did offer me a preview copy of the new one a while back) so I guess they are still working on the details.
The dates showing for me around that time are 6-May (first trip of the season), 13-May, 20-May, 27-May, 03-Jun, 10-Jun, 17-Jun, 24-Jun. The first two are cheaper and the last two in June are more expensive. I’m sure I read somewhere that something wasn’t open for the first couple of trips of the year but haven’t seen that mentioned anywhere since.