The Pioneer Girl website, which says "As always, any redistribution, reproduction or translation of part or all of the current or past contents of this site in any form is strictly prohibited. You may not distribute or commercially exploit the content, nor may you transmit content to or store it in any other website or other form of electronic retrieval system." -- I particularly like the "as always." The irony is sharper than usual here given the content of the website, primarily a factual account of Laura Ingalls Wilder's unpublished memoir and drafts of Little House books, with directions about how to get the microfilm copy thereof. I wonder about the copyright status of the drafts, which the site says differ from the published versions. These seem published (microfilmed and distributed); were they registered? The registration of the final versions wouldn't necessarily cover the earlier drafts.
ETA: Post edited because Pamela Chestek points out that the rule in Streetwise is that the registration does cover earlier versions, at least when the same entity owns both (which seems likely to be true of the Ingalls books, assuming the estate terminated any earlier transfer). But some courts have read Streetwise to cover only situations where the registration specifies the earlier works of which a registered work is a derivative, and I doubt that's the case here.