Got the email from B&K. ALL excursions on both halves of Sea2Sea are FREEEEEEEEEEEEEE!
That includes St Petersburg!!!!
I just looked at a review from someone who used Red October when sailing Voyager a few years ago; paid $1170 for the two of them for three days in St Petersburg. Free excursions could add up to a $2,000 or more for the two week back to back.
Now, I just have to figure out how to use $800 in shipboard credits for week on Navigator.