Get another wallet (such as hive) and send the BTC from Coinbase to that.
"help staple correct horse ..."
From there, just store that seed somewhere secure and you can use that to generate your keys whenever you want, on any machine you want. Personally I keep my seed in two different safe-deposit boxes and one on (shameless plug) my own encrypted text app I made called Onions - http://onionsapp.github.io.
Hmm, really? Why? The ledger sets up its own private key as well.