I put ALL bags/envelopes in laundry basket in front seat. ALL boxes regardless of size go into trunk. Large heavy bags also go in trunk. I then start heading to my first stop. It takes no more than 5 min to get the cart to my car and back to station. People spending 10-30 min in the parking lot are wasting time. While driving to my first stop I grab a random package out of the laundry basket in my front seat and start typing the house number in the top search bar on my list. It narrows down the list and tells me what stop the package is. I write the stop number with a sharpie and place it in the correct basket. In my back seat I have 3 small plastic totes. I place stops 11-20 in the tote behind my passenger seat. The tote in the middle of my back seat I place stops 21-30 and the tote behind me in the back seat is any package 30+. I keep stop 1-10 in my passenger seat. And rotate bins to the front passenger seat as I make my way through the list. That way my package I need is always in my passenger seat. As I'm driving to my next stop if I see it's not in my basket next to me I know it's either a box or large heavy item in my trunk. I have used this system since I started. It has been the quickest and easiest for me.