+1 for backup/restore

Main thing here is to test, test, test. I know it might be obvious, but you need to point your applications (as a test) to the test upgrade and see what works or doesn't. This will help you find holes.

Off the top of my head, these items need to be manually scripted and moved from source box(es) to the new one.

- logins

- linked servers

- jobs

- packages

- server certificates

- DDL triggers for the server

- server audits

- replication, perhaps dist dbs

- might have issues with security for any of these items

The DBs should move, and if you have the correct logins moved, likely no orphans, but need to check.

Lastly, run the upgrade advisor on each db. Make sure that you aren't going to get into issues there. MIght need to reduce compat level for databases.