On further reading it seems a more realistic question would be what the response would be to
Operation Wilfred, as R-4 was merely a pre-planned intervention after an expected German response. The immediate response of the Norwegian Government to the mining of their territorial waters was outrage and demands for their removal were made, but this was immediately superseded by the German invasion.
So, a short timeline of events that I am conceiving of are as follows;
-Operation Wilfred is completed uninterrupted.
-The Norwegian government is furious and makes demands for the removal of the mines.
-The British are obstinate and make facile claims as to the necessity of the minelaying and how their placement is only injurious to German shipping.
-International and domestic outrage is real but limited; No Allied invasion has been launched yet.
-The Germans invade.
-The Allies counter-invade.
-things proceed as per OTL, though likely with far greater German casualties due to lack of element of surprise and Allied naval intervention.
Honestly is seems like the entire German invasion of Norway was a terrible idea. When does the Baltic sea ice melt? June? I think the strategic value of Narvik is overblown, certainly not worth the invasion, I'm wondering what the the Generalstab was thinking.