Below, I'll write how you can move your site from Drupal to ProcessWire. It's quite simple.
In Drupal you will need:
- Views Module,
- Views Data Export Module,
- Views UI Module (integrated with Views),
- Chaos tools Module - required by Views.
Install these modules and switch them on.
In ProcessWire you need only:
- CSV Page Import Process (Import Pages from CSV).
Install this module.
When you are ready, you have to create a new View (select: "Create a page") in Drupal with all fields which you want to export. Then, add "Data export" subpage and make sure, that format is CSV file. It's a good idea, to use Pager when you have lot of nodes (pages). You have to setup an url to download your CSV files. When you are ready - download your data.
Next step:
In ProcessWire, you have to prepare a template with your fields. When that's finished, you can import your data from CSV files using "CSV Page Import". That's all.
If you have any questions, write them below. I can also write complete scenario for my website (if there will be anyone interested in that).