The keyword to search for is Schulungslager, this is what Nazi "re-education camps" were called. These camps were used for indoctrination not only of teachers but also other professionals. Here is an excerpt (discussing such camps) from the PhD dissertation
Forestopia: The Use of the Forest Landscape in Naturalizing National Socialist Ideologies of
Volk, Race, and Lebensraum, 1918-1945
by Michael Imort, Queen's University
Kingston, Ontario, Canada, 2000. Pages 270-272.
In National Socialist Germany, foresters were plainly drafted into public duty as "leaders." To prepare them for this task, foresters were called up into Weltanschauliche Schulungslager or 'ideology camps' to receive "ideological and physical training." The fact that foresters shared this 'honour' with relatively few other professions such as teachers and university lecturers indicates how important the National Socialists deemed the function of foresters as public role models and multiplicators in the rural districts to be.
For example, in 1935, all Saxon state foresters under the age of 55 had to spend one week in the NS-Gauführerschule (National Socialist District Leader Training School) at Augustusburg castle. At this 'boot camp,' foresters of all ranks (even full professors!) had to eat, sleep, and wash in common quarters with bunk beds, they exercised in "forest runs" and "battle games," they formed "potato-peeling kitchen detachments," and they had to pass spot inspections of their quarters while standing at attention in their pajamas. Yet the "strict regime of military and athletic duties" was only meant to provide the "framework" for ideological presentations as the core of the entire training.
The invited party speakers began by inveighing against the "ideological enemies": the "Jewry" as "the counter-race" and its "back-up army, the Freemasons and political Catholicism.'" Other speeches dealt with the "'racial problem" and - in an instance of early sabre - rattling - the "question of Czechoslovakia. Finally, the Reichsstatthalter (Reich Governor) of Saxony himself spelled out the purpose of this training camp:
"Apply and carry through in the outside world everything you hear and experience here. Do so as the loyal soldiers of the Führer - soldiers who can march and shoot if need be."
Regarding your question "What was it like for any participant who questioned the morality of the content?", I would regard it as "too basic": Questioning morality of the Nazi regime (in this case, of Nazi "education") would lead to a teacher loosing his/her job and, possibly/likely, further, to a concentration camp. Aside: Participation of school teachers in NSDAP past 1933 was quite high, if I remember it correctly, over 30\% after 1936.
The quoted dissertation gives references (all in German) to more detailed description of participants experience in Schulungslagern. If you are really motivated, you can get these sources through an interlibrary loan and either translate yourself or ask somebody else to translate these for you.