For RUHE check out:
http://www.ancestry.com/search/SurnamePage.aspx?sourcecode=13304&html=b&fn=&ln=Ruhe&submit.x=0&submit.y=0
(P.H.Reany, A Dictionary of English Surnames, Oxford 1997)
My book of German surnames (Rosa und Volker Kohlheim, Familiennamen, Mannheim 2000) gives a different explanation:
Variant of RAU(E) / RAUHE: from Middle High German "ruh, ruch, ruw" = "shaggy" but also "curt, coarse, impetuous" (I don't think it's connected with "raw" though)
KEMMERLING
Reany has:
http://www.ancestry.com/search/SurnamePage.aspx?sourcecode=13304&html=b&fn=&ln=Kemmerling&submit.x=0&submit.y=0
This seems to make sense with the first E taking the place of Ä (A umlaut), as would be in modern German (from "Kammer" = "chamber", in German a "small room"; "Kämmerer" is "treasurer", guard of the treasure-house = Schatzkammer). You will find the Word "Kämmerling" (with the A umlaut) for "chamberlain" in a modern German dictionary.
As the letter E can substitute any of the three umlauts, you might consider KÖMMERLING (with an O umlaut; this is a name I have heard of) and KÜMMERLING (with a U umlaut; never heard of). You will find both words in Grimm's dictionary, Kömmerling being a variant of Kümmerling. This can mean either "cucumber" or "darling" (i.e. object of someone's "Kummer" = care). The modern German word "Kümmerling" (not used very much) is "weakling" in English and this is another possible derivation of KEMMERLING.
So take your pick.