Google-chrome – Offline Evernote Access in Chrome

Seems like the Evernote folks have written something especially for this case:

1. Sign into Google Notebook
2. Click on a notebook that you want to export
3. Click the Export link at the bottom of the page
4. Choose ‘Atom’ from the export options.
5. Save the Google Atom Notebook file to your desktop

Then go over to https://www.evernote.com/GoogleNotebooks.action and just import the created "Atom".

Repeat for all notebooks.

Simplenote recently added Dropbox syncing as a premium feature:

Dropbox is a great way to sync files. When you link your Dropbox account to your Simplenote account, all your notes in Simplenote will appear as text files in the Dropbox directory of your choice. Thereafter, your notes and files stay synchronized as you make changes. Syncing happens in both directions.

In my experience so far, the feature has not worked completely. The changes I make to the text files in my Dropbox folder do not get pushed to Simplenote's cloud. But I am hopeful that this will be fixed soon.

Notational Velocity, a 3rd-party text editor that syncs with Simplenote, also supports storing its notes as text files, which you can put onto Dropbox. But this solution is far from optimal since this ties the Dropbox syncing entirely to the single computer that you use NV on.

I realize this answer only addresses one part of the your question--the Simplenote side--and entirely ignores the Evernote side:)