Yes, it is wise to plan ahead. You have enough to do when the time comes that she needs more care. My husband and I remodeled our home between 2005 & 2007 with just the plans that you mention. We completed remodeled the bathroom so we could install a stacked washer and dryer when the time came that we could to manage the basement steps. The kitchen was completely remodeled and other thing were done. Then the flood of June, 2008, destroyed our home and we had to move. We looked for home with no steps or stairs, and were fortunate enough to find one in our price range. I refused to purchase a home where we would have a mortgage at our age. My husband was 79 and I was 74. When he became so disabled that he needed a walker and then a wheel chair, we could come in through the attached garage into the laundry room without even a bump of an inch. Made all the difference

Best wishes to you and your wife, I know you will be fine with God's help.