Read up on Wannsee Conference.
Germany had trains, Poland had trains - more than enough to transport people - 250 per cattle car..
By the summer of 1944, IG Farben was providing 4 1/2 tons of Z-clone B to the SS per their bills of lading produced by the prosecutors at the Nuremburg trials after the war.
Bones were crushed by machines specially manufactured for the task and the remains and ashes scattered in the forests.
Read some accounts from those in the SS.
http://www.izieu.com/new_page_8a.htm
I find it hard to accept you can believe a delusional, illiterate farm boy but are doubtful regarding thousands of hard undeniable facts.
In 1942, the six Auschwitz ovens could have consumed about 4500 per month. The highest monthly death total for registered prisoners at Auschwitz was 9000 in September 1942. By the summer of 1944, an additional 12 ovens were constructed with a capacity of 420 bodies per day or about 12,500 per month. The Nazi records indicate they topped out 26,000 per day during the summer of '44.