There are several rafting companies, and both Omega Tours and Moskitia EcoAventuras offer a free night dorm stay if doing rafting through them (I like them both: Omega Tours has a very beautiful lodge, with pool and restaurant that makes a great getaway- Moskitia EcoAventuras has a more basic set up but is right on the river and has a kitchen if you want to make your own food, plus I can get you a discount if you want to book your rafting with them through me, and they'll include a pick up from the ferry dock).
My kids and I recently went over for the weekend, and this time we stayed at Moskitia EcoAventuras, though we walked across the road to Omega to say hi to our friends there and have a drink and an appetizer. We went to La Ceiba the day before we wanted to raft, and went up to the river in the afternoon to just enjoy swimming on the river and the beautiful scenery. If you don't want to cook yourself, the owner Jorge can arrange for a woman to come and cook for you for really reasonable pricing, so we did that for both dinner and breakfast. There are just a few rooms to stay on (Jorge plans to expand more in the future), as their main business is the rafting, with groups sometimes coming just for the day to raft (when we were there that afternoon, a group of 30 was in, but the next morning, we ended up all on our own for our rafting, with just our guide in our raft, and a couple other guides in another raft for safety- 2 other companies were also rafting at the same time, each with just 1 raft of customers). I didn't see that Jorge had any drinks to sell, so if you'd like a few beers or a bottle of wine in the evening, you'll want to bring one along, or just cross over to Omega Tours, which is just a few minutes walk (bring a flashlight).
The evening was really cool for sleeping- I was glad I had brought pants and a jacket! We planned for rafting the next morning at 9, and when I got up, I was thinking how cold it would be to get wet! But by the time 9 rolled around, the sun was starting to warm things up, and once we got down on the river, it was beautiful weather.
I've only been rafting once in my life, and my kids have never been, so I appreciated the thorough briefing and pratice paddling before we set out. The rapids that we went through were fun and exhilarating, but not terrifying, so newbies don't have to be scared about going. For experienced rafters who want more challenge, I think Jorge has other tours also available.
We were on the river about 2 1/2 hours in total, with a little break partway along to swim. Once we finished up, the truck was waiting to take us and the rafts back to the base. It was a great getaway (halfway through, Auri said 'when can we come back?'), and definitely worth adding a stop along your travels. It's also possible to do as a day trip from Roatan, either taking the ferry over in the morning and then the afternoon ferry back at night, or catching a flight over and back.