I asked about just this today, as I technically have a voucher now (once it arrives!) for a 4 day cruise.
Even though it's for 4 people technically, only my bf and I would go (those cruise rooms are tiny!). I asked if it was possible to upgrade to a veranda room (from the oceanview room they give us) and my guide said it would be $175 a person. Hope that helps someone!
Also, I believe the dates started this August, ran through March or so (roughly every week or so, I think). Then nothing again till August, I think, then it starts up again until the end of the year. But I believe somewhere on one of these boards someone posted a copy of cruise dates (like a scanned copy).