My restaurant recommendations:
1) "Mörwald im Kloster Und", Undstraße 6, Krems Tel. (02732) 70493,
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(closed on Mondays and Tuesdays)
2) Zum Kaiser von Österreich, Körnermarkt 9, Krems Tel. (02732) 86001,
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(closed on Sundays)
3) Landhaus Bacher, Mautern (4 km from Krems) Tel. (02732) 82937, 85429,
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(closed on Mondays and Tuesdays) (One of Austria's best restaurants)
4) Loibnerhof, Unterloiben (7 km from Krems, on the way to Dürnstein), Tel. (02732) 82890 (closed on Mondays and Tuesdays) Has a very beautiful garden - go there for lunch on a sunny day, preferably not on a Saturday or Sunday (too many people...). Take the train to Unterloiben (stop on request), walk down to Loibnerhof, have lunch, walk along the Danube to beautiful Dürnstein, then take the boat (or train) back to Krems.
If you speak some German, you may want to search on
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Thomas