Cassandra - reinserting a node
the first thing I'd worry about is zombie data. the data on your dead node might overwrite the data that you truncated. to be sure, I'd move that data somewhere else. also, delete the contents of the /commitlog and /saved_caches directories (or move them if you feel the need).

I'm assuming you have a suitable replication factor on your data? So there will be a copy of the data elsewhere in the cluster. When you re-add the node, the data will stream from the other nodes.