John, I'd recommend that you consult a Realtor in your area (you won't be under any obligation until you sign a listing contract but it's a great way to get to know some and establish a relationship with one now that you'll be in the market to sell in the next couple of years) who can help you determine that. From what I hear (but not being a Realtor who knows your specific market) eliminating rooms (by combining) can oftentimes backfire. While it may work for your family, it may not work for the next one considering purchasing your home, especially since most of the homes in your area have 4 bedrooms and I'd venture to guess they're all about the same square footage.
P.S. Thank YOU for the job you do in serving our country! God Bless you and your family!
"There's never a second chance to make a first impression!"