Take some advice from a "Non single guy" there is no winning. If the
vinyl doesn't turn out it will be your fault and held over you for the
rest of your time together. ;-)

That is a lot of adhesive to spread and spreading adhesive is a lot
more work than it seems like it should be. If you don't spread it
quick enough there will be places the floor doesn't adhear well. If
you don't spread it consistant enough the vinyl will not have a smooth
surface.

Get a pro or go with tile. There are many nice tiles at the home
stores for about the same price as vinyl. You can take your time with
tile and you will have a lot nicer / tougher floor when you are done
(Cermaic or natural stone).