It sounds like you're fighting Lightroom's natural workflow a bit. Here's my suggestion, which is pretty close to a "standard" workflow for Lightroom:

• Import your RAW files. As part of the import, you've got the option to move the files to another location -- that would be your external drive. Following the import, then, Lightroom knows about your photos, and the location it knows for those RAW files is the external drive.
• Keyword tagging and ranking in the Library module.
• Edit any photos you wish in the Develop module -- it's ok to swap this step with tagging if you'd rather do it in that order.
• Export your photos to your album folder.

At this point, you can disconnect your external drive and you'll still have the photos in your album. If you want to do any work with those photos, though, you'll have to have your external drive connected.

Regardless of whatever tuning you do to your workflow, you want to make sure that once photos become known to Lightroom, you're using Lightroom to manage moving those photos, if necessary. This is because Lightroom handles all of its manipulations and metadata as additions to your original photo (your RAW files). If you change the location of that RAW file in a way that Lightroom isn't aware of, you're going to end up having to help Lightroom find the new location for that file before it can continue.