I’ve written about this before but it’s so useful and magic-like that it bears repeating. The TL;DR is that when you’re in eshell, you can simply cd to a directory on a remote machine. Once there you can pretty much treat the remote machine as if its file system is mounted on your local workstation.
Alain Lafon has a short post that describes using cd to seamlessly log into another machine. You use the same syntax you would with Tramp to specify the path to the remote machine. Once there, you can copy files to and from the remote machine, load a file with the usual Ctrl+x Ctrl+f, or any of the other normal operations. As Lafon says, “It’s magic!”