Mundo Albiceleste user Abs has kindly passed along off the pitch information about Argentina's match against Saudi Arabia.
Here is the information:
The players will fly in to Riyadh through 2 different flights. However, both flights will land at the private airport. So, don't waste your time and wait for the players at the airport.
The players will then stay at The Ritz Carleton Hotel in Riyadh the hotel prices starts from around $200. I don't know how the security would be like, but if you aren't staying at the hotel then it'll be very difficult to just go visit.
I am not sure about the trainings, but I am sure it'll be the day before the game at the Stadium. And again, it is difficult to attend to the training unless you know people.
I don't have information about the tickets for the game, but am assuming the good seats are about to sell out, if not already.
Thanks to Abs for the information!