Residential Fridge install question

Thanks for all the replies and suggestions based on what you've done. I think I'm going to leave the roof vent open for now and put some foam insulation over the access door but leave the door functional in case I need to get in there for any reason.

Another question I have is what others have done with the freezer defrost drain hose? Normally it drains into a pan and then the water just evaporates from the compressor heat. I have a hose fitting from the old fridge that drains into the grey water tank so I'm thinking of removing the current drain hose flapper valve and connect the hose to the fitting that dumps into the grey holding tank.