We have returned from Berlin and would like to thank the Forum for the advice and to provide some feedback.
We chose to stay at the Melia which was really comfortable. We usually do not stay in Business Class hotels, so this was a new experience. The comfort of the room, king size bed, large enought room to do yoga, great bathroom, had a tea kettle and a mini bar (we essentially took the hotel beverages out and used the fridge for yogurt, cheeses, wine and other snacks which we purchased at City Market across the street). The sauna was excellent and the full size bathtub really was a pleasure after a day of walking. We ate at the Tapas Bar one night which was actually reasonably priced and tasty. We were glad that we had a hotel with a 24 hour desk when our train to Berlin arrives 4 hours late at 9:30 pm so were able to check in with no problem. (So much for the myth about German trains running like clockwork - that must be an old story.) The concierge was very helpful in helping us plan our walks and sightseeing.
The Melia is located a few feet from the S and U bahn stations on Friedrichstrasse, so it was convenient to get around to see the sights. We still walked miles each day.
That being said, if I ever return to Berlin, I may want to stay near Hachshermarkt as we kept going back to that station very often.
Of all the plans and itinerary that I created in my planning, I have learned that at 72 years old, we do not cover the same ground as we use to. We don't get out on the street until 10 or 11, so that cuts the day down, especially in the Autumn. And when I schedule a couple of Rick Steves walking tours back to back, what is suppose to be a 45 minute to 90 minute walk takes us 3 to 4 hours because we stopped every 10 feet to take a photo or look on a map or try to figure out what the GPS is telling us to do.
Berlin was very intense seeing all the history in person. Some of the highlights of our trip were the German History Museum (first floor 20th Century), Topograhy of Terror was excellent, Checkpoint Charlie Museum was also very interesting, Our first day was a visit to the Reichstag Dome - the security was a pretty rigorous, however, the views were excellent. The Pergaman was worth seeing, We really loved spending several hours walking the Eastside Gallery (I created a Mile of Mural Project in Chicago, so this was inspiring to me), The New Synagogue, Berlinishe Gallery and we saw some excellent exhibits at Gropius Bau. Hunting for RS recommended restaurants is always fun, but sometimes we just have to pick something and we had really good luck in finding great places.
Thanks again for all the advice.