Yes you can run a smaller belt and skip the pump, did this on my 94 5.0 and skipped AC and smog. I've got a routing diagram saved on my computer (I'm on my phone) it might take me a few days to dig it up but I'm sure someone on here can post one quicker.
What I did though was drive to auto parts store, told them what I was doing, they let me take about 4 belts to my car to try and buy the one that worked. Make sure you get the smallest that you can slip on that way when it stretches the tensioner will still pick up the slack.
04 3.9l Convertible- Daily driver
94 5.0l Convertible- Work in progress
92 5.0l Hatchback- Another work in progress