Uenoshi station of the Iga Line is the main railway station of Iga city and the conference venue, Haitopia building, is facing the station square. Also, any bus line stops in front of Haitopia.
Iga-Ueno station of the JR-Kansai line and Iga-Kambe station of the Kintetsu Osaka Line are the stations where you can transfer to the Iga line.
When you take a JR-Kansai train from Nagoya-Kameyama to Kamo-Kizu that stops at Iga-Ueno station platform 2, transfer to the Iga Line is very easy because the trains of the Iga line is waiting in front of the same platform. Settle the JR-ticket at the counter of the same platform and buy the ticket of Iga line in the train. However, coming from Kyoto, trains of the JR-Kansai Lline stop at platform 3 or 4. It results that you have to cross the overbridge beween platforms without lift. When coming from Kyoto via Kusatsu and Tsuge, the same problem occurs at Tsuge station upon transfer. Also, there is only one train in an hour.
So the use of JR-Kansai line from Kyoto may require strength and patience.

When you take Kintetsu rapid trains from Osaka-Uehonmachi, Yamato-Yagi to Ise-Nakagawa that stop at Iga-Kambe station, transfer to the Iga Line is barrier-free and there are 4 to 7 trains in an hour. Also, Airport limousine buses to/from KIX are available at Yamato-Yagi and Osaka-Uehonmachi stations in the same Kintetsu Osaka Line.

Transfer from JR-Kansai Line to Iga Line at JR-Iga-Ueno station is easy but the train frequency is quite low. When using Kintetsu Nagoya Line from Kintetsu Nagoya station: E01 to Iga-Kambe station: D52, change in train may be needed at Ise-Nakagawa station: D61. These train travels are recommendable but less convenient than using buses.

First, take Airport Limousine Buses of Kintetsu bus (bus stop #7 at Terminal 1 and #8 at Terminal 2) or Nara Kotsu bus (bus stop #9 at Terminal 1 and #5 at Terminal 2) to take the Kintetsu Line.
Kintetsu bus starts every 30 minutes and takes 50 minutes to Osaka-Uehonmachi station :D03 at a rate of 1550 yen. The bus termnal is the ground floor of Sheraton Miyako Hotel Osaka and its B2F is Kintetsu Uehonmachi station: D03. Take fastest train for Nagoya and transit at Iga-Kambe station: D52. The rate is 2040 yen. Reservation is not necessary.
Nara Kotsu bus starts every 60 minutes and takes 70 minutes to Yamato-Yagi station :D39 at a rate of 1950 yen.Take fastest train for Nagoya and transit at Iga-Kambe station: D52. The rate is 1590 yen.
Ticket of Iga Line can be purchesed in the train and get off at Uenoshi station. The rate is 360 yen. Choice of the above two options may depend on the timing of the bus available at KIX. When going back to KIX with Nara Kotsu Airport Limousine bus at Yamato-Yagi station, reservation is required but not always necessary. See below for the combination of Mie Kotsu bus to JR-Shin-Osaka and the JR limited express train "Haruka".

Unlike arrival, use of JR-Kansai Line to go out from Iga is not recommendable due to the train frequency and the overbridge.
However once in Nagoya station by bus or Kintetsu Line, use of Meitetsu Line from Meitetsu-Nagoya:NH36 to Centrair railway station: T24 is convenient because of train frequency and long operation time from 5:24 to 23:31. Transit between stations of Kintetsu-Nagoya and Meitetsu-Nagoya may be a challenging city walk.

Transfer from Iga Line to JR-Kansai Line at JR-Iga-Ueno station is easy though the train frequency is quite low. If you check the timetable carefully, train transport from Uenoshi to Kyoto is fine.

Because there is no direct bus from the airprts to Iga, you have to change buses at bus terminals where availability of lifts and escarators is a key issue.

Airport Limosine buses are available both at KIX and Centrair, and probably the easiest way to depart from the airports with baggage. The color of the bus varies according to the operating bus companies and reservation is normally not necessary.
Bus ticket can be purchased normally with vending machines with a small money but use of credit cards is not possible. Use of IC card instead of ticket is possible in a limited number of companies.

Direct bus from Kyoto to Iga city is currently unavailable. From KIX to Iga, use of the fixed-rate taxi may make sense if you are a group of more than two. Rates are 17500 yen for two with 3 bags, 19500 yen for four with 3 bags and 29500 yen for five with 3 bags. A highway toll is not included. Meeting point is MK Taxi counter at the H exhit of the KIX terminal 1 arrival lobby. On-line reservation may need a Japanese assistant.

From Iga to JR Shin-Osaka Station, you can take  Mie Kotsu highway bus starting 4 times a day and then take JR Express train “Haruka" to KIX.
Example: Haitopia Iga 14:40 or 16:15 -> 16:33 or 18:08 JR Shin-Osaka  station, Limited express “Haruka” 17:00 or 18:30 ->17:55 or 19:25 KIX train station.
In JR Shin-Osaka station, the Mie Kotsu highway bus stops at the North parking area and it takes 5-7 minutes on foot. It is not sure you can find a lift so easily.

Conference chartered buses will start from Haitopia to Kyoto stopping at the JR-Kyoto station Hachijo-guchi and near your hotels in Kyoto on 19 th night and 20th evening. Airport buses to KIX start at the bus stop H2, in front of Avanti building, and the driver and assistants help you for baggage loading and ticket issue even if you have no IC card with you. Airport buses go every 20 minutes in the daytime, 30 minutes from 18:00 to 22:10.