The websites won't matter where you go for pricing for Royal (don't know about Princess line). Royal's policy on cruise prices is that any Travel Agent, Website, etc. CANNOT
sell below their cost.
I would book the trip through a Travel Agent. It's better in case there are any questions or problems.
Serenade of the Seas is 7 day in the Caribbean. It'll be nice that time of year since people are running around Christmas shopping here in the States so it might not be that crowded. The ship itself would be perfect for you guys (at least in my opinion anyway).
I have photo's posted over at www.webshots.com
. Click on the Community button at the top. When that page comes up, scroll to the bottom & under the Find Member, type in Cassie4486. My album will come up & you just click on the link. Has photo's of the ship & the islands along with descriptions of each photo. Enjoy!!!