I was on the Paradise this past May.
For both of these islands, it is best to have a plan, especially in Belize.
Outside of a very small shopping area where the tenders let you off in Belize, there's not much else unless you do a ship-sponsored excursion or book through a private operator. They will not harass you like in Jamaica there. We booked a full day wildlife sightseeing and snorkeling adventure through Sea Sports Belize, and they were EXCELLENT. I Highly recommend them. Snorkeling and diving are the big things to do in Belize. Also there are ruins and jungle river trips, which are nice. This is not the place to go shopping.
As for Roatan, yes, it is a very, very poor, but very beautiful island. When you dock, you will see a big anchor fence with lots of natives behind it. They are mostly private tour operators or taxi drivers, and they are all safe. I know, the fence looks intimidating, but they are decent people looking to earn a living in a poor place. If you opt on using a private operator in Roatan, do not pay the published prices that you will see at the dock. EVERYTHING is negotiable there.
If you walk around Coxen Hole (where dock is in Roatan) you will be approached by natives looking to sell their wares or braid your hair, but if you say no thank you they will not harass you there. We took a taxi to the West End in Roatan. Nice beaches and shops, great snorkeling. We felt perfectly safe.
The Paradise Western route is unique because all four ports are very, very different. You will see. What an adventure you will have!!!!