A practical option is to review images through a cloud or transfer app rather than relying only on the iPad’s Photos app.

From the answers given:

• Dropbox can work well: copy your originals into a Dropbox folder, browse them on the iPad, and delete unwanted files there. This gives you folder-based access and avoids the Photos app’s limitations.
• Photoshop.com Mobile was also suggested as another app-based workflow for viewing images on the iPad.
• If you’re open to extra hardware, an Eye‑Fi card plus its iPad app was suggested for wirelessly sending photos to the iPad for review.

So if you want to use the iPad largely “as is,” a file-sync/app approach like Dropbox is the simplest fit. If you want direct transfer from the camera without cables, a wireless card solution such as Eye‑Fi is another route. The key idea is to use an app that manages files more flexibly than the default Photos app.