Make the bathroom as spacious as possible and try to include a large pantry within the room, not in an adjacent hallway. Try to design the laundry room as a separate room if at all possible. Do not succumb to the temptation of using it as a hallway from the garage to the main portion of the house. Be sure that there is a pantry in the laundry room or plan for plenty of wall space for storage cabinets. Create an alcove or nook for the home-office computer and desk setup.
Many people just plan to place it in a room.
The trouble is most people are not neat, and the desk looks like a disaster zone. If the desk and computer are in an alcove flanked by pocket or bi-fold doors, you can hide the mess in a matter of seconds, just before guests arrive. The space over the garage needs to have full attic trusses or at the very least affordable storage trusses. Plan for a real disappearing staircase for safe access to this supreme storage space. Finally, have the electrician install numerous strategically placed exterior outlets in the front and rear of your home for your festive holiday lights.