Yes, you can cut a hole into the floor to get at the fuel pump, but it's not that difficult to lower the tank to replace the pump. You don't even need to completely drop the tank. Just raise the driver side of the van, then start lowering the outer edge of the tank (after disconnecting the lines). As you lower it, at some point you will see that you can start getting at the plate that the pump is mounted on. No need to get destructive on your van.