I agree with SJOGuy about the river lodge. I've never been in Puerto Maldonado, but I've been in Iquitos (near Amazon river) and hotels within the city are not the best option if you want to live a real jungle experience, though the fun of a tropic town, nightlife, etc. is another story. But if you want an "adventure" experience, look for river lodge within the jungle.

However beware of the touristic tours visiting jungle tribes. Most of them are fake. The jungle trekkings are more authentic. I think a good guidebook will tell you about it