OP has picked his cruise, and I'm sure they will enjoy it.
One thing to consider in choosing a cruise line.If you look at the prices for the "Premium" lines (Viking, Seabourn, Oceania, Crystal, Azamara) and compare them to the "Mainline" lines (Princess, NCL, Royal, Celebrity, etc.) you might get sticker shock.
However, many are much more inclusive. Crystal is our favorite, and has gone all-inclusive now. Wine, drinks, tips, all in. And the service is unquestionably more attentive. So the price difference is significantly less.
We took Alaska in successive years, on Oceania then NCL. Same company, but night-and-day difference in service and food.
From less to more pricey, our favorites: Princess>>Viking>>Crystal>>Seabourn.