Why would Huck and Jim prefer the raft to any other home? (CH 17-19)

Chapter 18

"There warn't no home like a raft, after all. Other places do seem so cramped up and smothery, but a raft don't. You feel mighty free and easy and comfortable on a raft."

Obviously Huck's connection to the river is one important theme in this novel. Huck feels close to nature, and so is most comfortable on the raft. The raft, although small, opens up Huck to the world of nature - he could pull in to the shore, he could dive into the water, he could continue to float endlessly (or so he believes). His definition of home is very different from that of the people he has previously associated with. This is not a place he has to try to escape from.