Originally posted by drugal YMMV, but I'd say that you should keep the K-r in the end because:
1) Your girlfriend/sister are probably not into photography as much as you so they would probably like the slightly easier use. Having the camera choose Continuous/Single auto focus automatically, for instance. Furthermore, I'd guess that you won't be needing the weather sealing for these walks.
2) The better dynamic range of the K-r would help to prevent blown highlights, etc. and probably make them happier with the results.
3) The mass of the K-7 is also 150g more than the K-r, which may be a factor.
True (:
I guess I can just wait for the k-5 then.