Which Neighborhood?

I like Beyoglu near the New City and the commercial Istiklal Cadessi (street). Most tourists stay in Sultanahmet/ Old City to be walking distance to most attractions. The downside of staying there is you will stand out like a sore thumb and be hassled by touts on a daily basis (it got really old for me, but then again I was a single female traveling solo). That's why I like Beyoglu and neighborhoods across the bridge better; just beware, they are very hilly. Also the areas going north along the Bosphorus are just gorgeous (Ortakoy, etc).

Most kind, I will investigate. Thank you.

We stayed in two different neighborhoods, Sultanahmet and across the inlet near Taskim, Beyoglu. We much preferred the second area. Sultanahmet does have the historical sites but it also has lots of tourists and tourist restaurants. For a better experience, especially in dining, do not stay there.

Thank you all. I think our solution will be to stay in the old city for 3 nights in a hotel, then across the river for the final 3. We arrive late on a Sunday, and so I think a hotel, one which provides airport shuttle service, will be the best fit, at least at first, and after 20 hours of travel.

If I may, I would like to recommend Hotel Nena. It used to offer free airport shuttle with 3 nights booked. Great breakfast buffet included, and if you can get the 3rd floor suite, a deck with fantastic view of the Hagia Sofia.

If arriving Sunday, Monday will have a number of museum closures. Topkapi Palace is open that day, so does tend to get crowded. It is the only place I started to loose my cool with the tour groups that move en mass with no consideration of any others. Literally and physically pushed out if place. But, I have the height advantage, and took a deep breath, moved back and waited 3 minutes and they were gone. The typical recommendation is to go early, but maybe afternoon would be better.
I guess it also all depends on whether they require bookings now due to distancing.
I did get the museum pass for Istanbul. It is one place it seemed to pay off. You had to stand in line first museum to buy it, but then you could avoid the lines and I saw some museums I wouldn't have normally visited as they were free. Again, depends on the covid rules in place.
The Basilica Cistern is interesting and atmospheric. There are a number of cisterns and water catchments in the city.

I will be there in December so this is a good thread. Thank you.