The problem is, how many routes can one take to get to point A to B without backtracking? I know that I can solve this by assigning numbers to the intersections and that the intersections add up. However, I got stumped at certain parts because of the two rectangles. I might have also gotten some parts wrong. Any help is appreciated. Thank you!

You have done everything correct so far. You just missed a couple intersections, circled below. Keep filling them in as you have done so far (I did one more for you). The bottom right intersection will contain you answer when you are done.