Here's what I've seen:
*** w61 8/15 p. 503 "From House to House" ***
In the Greek text the word "houses" (oikous) follows the Greek preposition katá and is in the accusative case, plural. On the use of this preposition katá with the accusative case the book A Greek Grammar for Schools and Colleges, by Hadley and Allen, says on page 256, under katá: "with accusative . . . in distributive expressions: katá phyla by clans, each clan by itself, katà dyo by twos, two by two, kath’ hemeran day by day."
Says the book A Manual Grammar of the Greek New Testament, by Dana and Mantey, D.D., on page 107, under the heading Katá: "(3) With the accusative case: Along, at, according to. Luke 10:4, . . . ‘Salute no one along the road.’ Also in the distributive sense: Acts 2:46 kat’ oikon, from house to house: Luke 2:41 kat’ etos, from year to year; 1 Cor. 14:27, katà dyo, by twos. See also Luke 8:1; 13:32."
Quoting from still another Greek authority, that of Handbook to the Grammar of the Greek Testament, by Samuel G. Green, D.D. (Revision of 1912 edition), on pages 248, 249, under katá, it says: "ß. With the Accusative. . . . 4. Of place or time, distributively, from one to another. Mark xiii.8: seismoì katà tópous, earthquakes in diverse places. Luke viii.1: diódeue katà pólin, he was journeying from city to city. So kat’ étos year by year, Luke ii.41; kat’ oíkon, at different houses, Acts ii.46, v. 42; katà pan sábbaton, every Sabbath, Acts xv.21;" and so forth.
To quote just one more authority, there is also the book A Greek-English Lexicon of the New Testament, translated, revised and enlarged, by Joseph Henry Thayer, D.D.; on page 327, under the heading Katá, it says: "II. With the accusative: . . . 3. it denotes reference, relation, proportion, of various sorts: a. Distributively, indicating a succession of things following one another, a. in reference to place katà polin, in every city, (city by city, from city to city), Luke 8:1, 4; Acts 15:21; 20:23; Titus 1:5," and followed by a number of other references. Other grammars could doubtless be referred to to substantiate the distributive use of the Greek preposition katá with the accusative case as found in Acts 20:20.
*** w91 8/1 p. 24 "From House to House" ***
German scholar Hans Bruns justifies his translation, "from house to house," at Acts 5:42, saying: "According to the original text, it seems as if they went from house to house." Yes, kat´ oi´kon, the original expression in this text, is not used in an adverbial sense ("at home") but in a distributive sense, literally meaning "according to house." (The plural form, kat´ oi´kous, meaning "according to houses," is found at Acts 20:20.) Other scholars, such as Heinz Schürmann, substantiate the distributive translation of these expressions. Horst Balz and Gerhard Schneider, publishers of an exegetical dictionary to the New Testament, say that this expression can be rendered "house after house." A number of English reference works explain this verse similarly.
New World Translation Footnote:
*** Rbi8 Acts 5:42 ***
Lit., "according to house." Gr., kat´ oi´kon. Here ka·ta´ is used with the accusative sing. in the distributive sense. R. C. H. Lenski, in his work The Interpretation of The Acts of the Apostles, Minneapolis (1961), made the following comment on Ac 5:42: "Never for a moment did the apostles cease their blessed work. ‘Every day’ they continued, and this openly ‘in the Temple’ where the Sanhedrin and the Temple police could see and hear them, and, of course, also ?at’ ? ? ???, which is distributive, ‘from house to house,’ and not merely adverbial, ‘at home.’ "