I would like to thank drib for his wonderful site. You can search each Regent cruise for per diem cost with or without air. A real easy way to see the best deals publicly available in USA. Maybe someday he will include combination cruises in his relational database (hint) but even without that I find the site invaluable.

Marc

edited to add: drib had added the Navigator Grand Arctic Adventure in 2021. Just went to his site and was amazed that Regent just raised the price $200; I guess demand must be great.