If I may make a suggestion. Take a copy of Mark and put it on the word processing software of your choice. Go through it line by line and search to find what the lines echos, where it comes from. When you find a match highlight it. Then do the same for every line that the author is making fun of the apostles.

Nearly the whole book will be highlighted. Mark built Jesus out of Elijah and Paul. The so called oral tradition is like 20 lines or so.