vik, It sounds like you have a good foundation to be built upon. Most of the unspoken communication will come with time and experience. You do have to be watchfull...the tandem does take the best of the two riders, but it is easy for the stronger rider to overshadow the weaker. If your stoker is so slow on her single, there is a good chance that you are doing more than your share of the work! Try to be mindful of your effort as compared to your normal single riding. Of course, this can't be compared on the hills, but can be on the flats. Also, let the bike go-let it accelerate on the downhills, because you are at a disadvantage going up. If you let it go, you will really enjoy rolling terrain. Do be carefull not to scare your stoker; it is a blast for you to fly downhill at 50+ mph, but not so for a new stoker who can't see forward and has no control over the brakes.
Speaking of my own experience, it took me until about the age of 58 to gain enough maturity to realise that my wife and I ride for different reasons. I like to spar a bit with my riding buddies, but she is content to just cruise. I was always driven to do long distances; she draws the line at 35-40 miles (or sometimes less). Once I stopped trying to force my ideas about cycling down her throat, both of us started to really prefer the tandem to the singles!