We did a similar cruise/land tour on Coral Princess last summer. Fantastic! We took a 6 day land tour including Fairbanks, Denali and Copper River and then sailed with Coral from Whittier. The land tour and it's excursions were great fun and the following cruise was just wonderful. I just wish we could do it all again this year.
Highlites? - river cruise from Fairbanks, Denali National Park, dinner theatre at Denali Lodge, seeing Mt Mckinley, Copper River and surrounding area on a nature walk, boat transfer from Valdez to Coral Princess, Glacier Bay (with Champagne Breakfast), Helicopter landing on glacier, the train excursion from Skagway.
Sorry, we haven't had a PH, but we did really enjoy our balcony. I am sure the service on Sapphire will be excellent just as it was for us on Coral.
You will have a great holiday.