What are my (hardware) options from migrating an account from an MBA? I just got a shiny new rMBP 15" and want to migrate the account from an older Mac - I've been using a late 2010 MBA. The Migration Assistant estimated 50 hours over the WiFi, after an hour it got up to 60 hrs. It's an MBA, so no ethernet for me, also no Thunderbolt (late 2010s didn't have it yet).

Are there any other options available? Can I force the Assistant to 'migrate' to an external drive somehow, and then import that to MBP?

Maybe there is a step-by-step guide to migrate 'by hand' using a USB stick or something?
The best way to migrate is to make sure you have a current Time Machine backup and just restore from that volume to the new machine. I have restored from a Time Machine backup to an empty formatted hard drive and it worked perfectly, including my custom FTP, HTTP, and git configurations. It took about 10 hours for a 1TB backup.