You need to get some graph paper and draw your plan out to scale. Then make cutouts (to scale) of your washer/dryer, sink, etc. Then start placing various things around on the graph paper. Think of where you are going to vent your dryer and run the plumbing. And because of freezing issues you may not want your plumbing on an outside wall.

Be aware that your door openings have to be big enough, (also remember corners) in order to get your washer/dryer units thru the doors.

Personally, I would arrange it so the half bath was in front and then put up a sliding pocket door to get into the laundry area. I would not want to constantly keep the laundry area pristine in case of guests wanting to use the bathroom. Again if you do something like that, make sure you can get your units thru all the openings.