The field trip itself was okay. I'd never been to the palace, nor to Queen Emma's Summer Palace. I can now say from first-hand experience that these historic sites fully met my expectations.
In other words, if you're planning to do the tourist thing in Honolulu, you can skip the "palaces."
Almost every city or town has a "restored" Victorian-era home furnished with turn-of-the-century bric-a-brac. If you've seen your own local lumber baron's or mining magnate's or railroad tycoon's restored 1880s home, you've seen Iolani Palace and Queen Emma's house. The paintings on the walls are different -- here, it's photos and paintings of Hawaiian royalty. Where you live, it's the family of the guy the grade school and the performing arts center are named after. Here, it's the "grand koa wood staircase." Elsewhere, it's the grand douglas fir, sitka spruce, red cedar, quartersawn white oak, or imported Honduran mahogany staircase, depending on local availability or ostentatious trend of the decade. Other than that, it's the same furniture, the same porcelain vases, and probably the same questionable level of "selective authenticity" to the restorations.