If you want to get there by public transport, then I recommend from Istanbul (Otogar subway station) to get to Canakkale - time in way around 7 hours, 3 flights per day are carried out. In Canakkala, change to dolmush to Troy (Truva), go for about 30 minutes

At the moment, none of the tour operators conduct such an excursion. It can be ordered individually, but very expensive. Travel time from Istanbul to Troy is 4-5 hours. Therefore, even on an individual basis, it is recommended to do it for 2 days. But if you go on vacation in Kusadasi (flight to Izmir), you can see Troy with a group of excursions and inexpensively.