We booked this two days ahead while already in Istanbul to fill up an otherwise open Monday. When we found out that Dolmabahce Palace was closed on Monday, we contacted Viator and were able to change it Sunday instead - Thanks. Note to Viator, don't sell this tour on Mon/Thur when the Palace is closed.
Here is your day:
Pickup in shuttle van in the morning. Taken to muster point where a number of tours then reassemble and depart on two decker tour buses (open upstairs).
First stop is the spice bazaar. You're given about 45mins to stroll around. Once you've been in the first shop or two, it's more of the same.
Next up is the 90 min Bosphorus cruise. Hopefully you'll have a fine day where you can enjoy the terrific sightseeing up one side and down the other. The boat was clean, open and offered great views.
After that, you're taken to a "leather demonstration". This is no more than a cheesy leather jacket fashion show, after which, you're hustled to their showroom where 50% discounts off inflated prices are offered. We chose to sit outside in the sun instead.
Conveniently, the lunch restaurant is next door. Lunch is simple and everyone else in the restaurant is doing exactly what you are - taking a break from their tour.
After lunch is the Palace. This is truly a highlight of the day (along with the cruise) as you gaze in awe at the amazing splendor that rivals anything in the world.
When you reassemble after some free time in the palace gardens, it's off to a trip over the Bosphorus Bridge, then on to a snack restaurant that overlooks back to the European side. There were no available tables or chairs for our tour, so everyone just milled around for 45 mins.
You are then dropped back at your hotel around 6p.
This is a good way to do both the cruise and the palace, along with some guided narration. The leather demonstration was meaningless and if you don't want to make the trip to the Asian side, you can always leave the tour after the palace.