Ok here is a floor plan, I am apprehensive to convert the garage since it is one of the big things pekoe look for when buying a house and we aren't going to stay here forever. Also the lot is an acre so adding to the back would be great HOWEVER about 5 ft off the back of our home is our septic tank under the patio :( here are some additional photos from when we bought the house.so basically we have an L shaped ranch. The office needs to have a door that closes and not be in too high of a traffic area as I work on the phone 40 hrs a week from home. So the mudroom is ruled out since the dogs live there and the laundry room and it is the main entrance. BuT we do not use the front door off the front porch often because there is no parking in the front of the house.

After seeing these pics and your floor plan, would it be possible to convert only one side of the garage to a "home office", leaving the integrity of the garage in tact so that it could be converted back to a garage when you sell? That way the new owners would have the option to just leave it a one-car garage and have an office space, or, very inexpensively, convert it back to a two-car garage.

That is a very good option. Do you have a picture of what the home may look like with the cape cod look you were referring to in the first comment? Also I have this picture but I am unsure because most homes with enclosed front porches have a porch all the way across the front not just the center like ours.

And we don't have those dormers to add to the curb appeal.

Actually, what I had in mind is very similar to what you posted. You could have faux dormers added on top of existing room for curb appeal. I would inset the front door to give it a little dimension, though, IF you go that route. However, I really wonder how much square footage you'll gain for the cost. It doesn't seem like very much.

If I were in your situation, I'd seriously consider the garage route. You could leave the existing concrete floor and add rugs, etc. I don't really know exactly what you need for office space, but it could be made comfortable. For walls, a simple 2x4 wall (insulated) could be added down the middle of the garage. You could either leave the garage door or add in French patio doors in it's place. Practically speaking, I'd leave the garage doors (put black paper on the backside of the glass for privacy). Then, if needed, the 2x4 wall could come down in the future. As for heating and cooling, investigate some "nice" portable heaters and air conditioners. My BIL added one to his converted garage in lieu of ductwork and it's very non-intrusive and is not tacky, which may or may not even be a concern :)