Assuming that it's a weekday it would take around 45 mins to an hour.
If it's a weekend, the journey may be shorter.

Also, the bus would pick up passengers at several points and the number of passengers waiting would affect the travel time.

Airport or hotel van?
 

€160 for an airport transfer is %100 A TOURIST SCAM and avoid it unless you are a billionaire and unless you like spending money too much.
There are luxury taxis at the airport ( Mercedes Vito ) which would charge you the double of the taximeter and would cost ( €40-50 ) o/w. You could put your carry-on bags inside the seating area and your bags back in the trunk. ( I am not sure if 6 large suitcases would fit ). The other option would be to split into 2 regular taxis which would cost the same price.

In your case, the information about the sizes of suitcases would help the most.

To put it in perspective, that amount is currently a bit over 1300 TL. A normal taxi should not cost you more than 120 under any circumstances, possibly as little as 100 TL. Listen to IST's above above. That number word is robbery...... And you are worried that the taxis were doing you off......

Let's see what kind of a "luxury lounge" this one is going to be. My rather distant information is that it's going to be smaller thatn the current two lounges, in area.

https://airlines.einnews.com/article...ontent=article

Seems like they have changed their policy to somewhat better conditions

https://cimg7.ibsrv.net/gimg/www.fly...7a1353036b.jpg
.

Unlike TAV, which could talk about "all" the other airports that you had access to, IGA is a one trick pony. Let's be serious here. The IGA lounge is mediocre at best, now that I have been through it 3 times (vs. the TK lounge that I have been through 11 times) I can say that it is really disappointing just how mediocre it is.......they had a chance to do something extraordinary....and then even handed a lifeline to "BTA" the worst caterer in Turkey.............who we all know from the horrible catering they provided at the Millenium lounge among other outlets. Assuming that one already has one or many flavors of elite status, the only thing that anyone would really care about here is the buggy service...............Having used the buggy service, I can say that they barely have enough of them, and they keep people waiting.......they can barely handle a half full KE Biz cabin, let alone a serious amount of passengers. I heard it through the grapevine that someone high up at IGA has been looking at these boards occasionally and presenting insights that he has found as his own brain storms....................So Mr. IGA, if you are reading.............. Come up with a good fast track and buggy deal that works for the ISt based road warrior who also travels with his family a few times a year, no "city transfers" no meaningful "valet parking", just stick with that and the "priorities". DO it at the first price point and you will have many takers...........

My impression of new IST is mostly about very poor layout planning. I can understand the Grand Bazaar logic of those in IGA who placed all transit security checkpoints in the centre of terminal to make every passengers go through shops... But this logic fails to see that this extra mile running across the whole terminal to checkpoint and back to the gates steals the very time the transit passenger would have otherwise spent in shops or restaurants. I'm sure the commercial result of this bazaar tactics is zero or even negative.

And it also denies TK the possibility to sell short connections, thus spoiling the home airline commercial strategy. Which is totally beyond my understanding.

As TK now has a share in IGA, I hope they would make an effort to install additional transit security facilities between A and B gates and another one at F gates.

Just wondering - is placing TK lounges entrances at E1 and C1 also the result of IGA's desire that premium passengers should pass some shops along the way? )

Seems like several routes of Hava.ist shuttle buses have been recently cancelled / merged into other routes / converted into regular IETT city buses.

Currently there seems to be 12 Hava.ist shuttles (or 15, including variations), instead of initial 20 in April - June, and 6 IETT regular buses instead of initial 3.

The reason for this is that they have planned Havaist shuttles and IETT ( municipality buses ) at the same exact route. Ex: Halkalı, Mahmutbey and Mecidiyeköy lines
Also, the Arnavutköy and Göktürk/Kemerburgaz shuttles were aiming airport employees however, they prefer to use buses because of the monthly transportation card they are getting from their company.
For the Zekeriyaköy route, I would comment that there would be just a few people in that area using those buses as someone who could afford to live in a €1m+ plus house, could afford to pay a private transfer or a carpark.

IST, when do you think we are, 2013? While there are a few crazy villas at that price, that are not typical of the area (10 bedrooms, lots of land) I would posit that the average villa price currently is something like 3-400.000 Euros, not 1 million PLUS. Furthermore its a buyers market..............

Trying to get some insight into this airport. A friend of mine is having her 13 year old fly solo from ACC to LAX via IST. Since she will be also be connecting to either a Swiss or Lufthansa flight, unaccompanied minor is not an option and both airlines would allow her to fly alone. Flight from ACC to IST seems to be delayed a lot. How much time do you really need to connect? From what I can see, TK630 typically lands at a B gate and the connecting flight is out of either A or B gates. Since Zurich airport is much simpler than Frankfurt, the preference would be for her to continue with Swiss but that would mean only 1 hour 40 mins for connecting assuming flight is on time. Frankfurt would allow 2 hours 15 mins which is a bit more reasonable although it would mean facing a bigger airport as a 13 year old.

Also any advice for how to navigate this airport step by step for a 13 year old so she can make it to her gate with a bit more ease? TIA

I don't quite get the route.
Is it ACC - IST - LAX? or ACC - IST - (ZRH / FRA) - LAX? or are they choosing between IST, FRA and ZRH as a transfer point?
If it is ACC - IST - (ZRH / FRA) - LAX, is it TK or LH / LX, who flies the second segment? Is it all on a single ticket?

Single ticket but choice of flying to either Zurich (Swiss) or Frankfurt (Lufthansa) to connect to LAX. The flight to both Zurich and Frankfurt are on Turkish.