I think your wife has some unrealistic fears. There is no reason to worry about traveling to Alaska on your own.
Try getting a Milepost and just have her look through it carefully. She will see there are a plethora of services all along all the routes to Alaska.
And in fact if you break down along a quiet stretch of road you will probably get help sooner than if you breakdown in some Lower 48 major metropolitan area. In fact the next car truck or RV will undoubtedly stop to help.
Don't worry just go. My first trip was in 1972 or 3 (cant remember) the road and trip was much different then. Today it is as easy as driving almost anywhere. Just way more beautiful.