/cgl/ - Cosplay & EGL

I'm trying to make Gyro's pants (tan/purple ones) out of an existing pair of pants. What I want to do to them is add the purple bits.

I'm having trouble positioning the pants on my sewing machine, because in order for me to be able to reach the inside of the pant leg, I end up with a ton of the pants fabric bunched up and squished in between the needle and the house of the machine(i don't know the right terminology for that part, its the big gap in the center of the machine if you are facing it head on). It is really difficult for me to have the fabric bunched up like this and also keep the part that I am sewing flat so that I don't get any puckers in my seam.

Is there any trick to sewing in the middle of a pair of pants like this? Or maybe I am approaching this all wrong? Should I be hand sewing this instead of trying to use my machine?

Any help is greatly appreciated. I am pretty inexperienced with sewing.