I have not stayed at Treetops, but I would as I've heard so very many good things about it. If you'd like to know more about Treetops or other hotels, go to belizeforum.com I was in CC for 3 wks during low season, met sev'l folks who stayed/had stayed there...all good. A few slight negatives but nothing significant. All said great value for price.
Maybe it's just me, but I'd like to do a little more upscale for my honeymoon. Check out Chocolate's room, if it's available. Lan Sluder of belizefirst.com rates it highly. Chocolate is amazing, an island legend...do a search on him at belizeforum.com
The forum is very informative. I used it almost exclusively to research my own trip...oh, I used other sites, but found the forum & belizefirst to be the most valuable for me.
Some folks say that 3 wks on CC is too long. Not so. You can do most all trips from CC, snorkeling is great, swimming at the split very pleasant, music is amazing, so is much of the food (simple pleasures!), sunsets & -rises, etc., etc. And staying that long allows you to get to know some of the shopkeepers who are all local & many Belizeans & CC'rs. Good people, interesting, friendly....Can you tell I loved it? Going back for 2 weeks this fall.
Try jungle/manatee trips w/Chocolate, snorkeling w/Carlos & Salvador, def do Goff's Caye, Hol Chan, Shark Ray Aley, sunset/sunrise canoe round-the-island w/Allie @ Cayboard Connection. Guatemalan coffee, bread and fruit at Cindy's, lunch/dinner at Syd's, lobster and conch fritters at Sandbox, etc. etc. sniff....sniff...I miss CC!! Have a great trip & a great life together.