Gambarini is part of the 41-man group due to train in Pensacola, Florida, next month, and is expecting to be put through his paces.
He said: "From July 1 we are training in Pensacola, Florida. We know that is going to be very hard in every sense, physically and mentally."
Gambarini is battling for a place with Alumni hooker Alberto Vernet Basualdo and is conscious that one of them is going to have to watch the tournament on TV.
"There is a friendship between us, but everyone is fighting for a ticket and there is a lot of competition," he said.
"We all are going to do everything necessary - in the right way. Today I have a 50 per cent chance of going and he has the other 50 per cent. In July, Loffreda will have the last word.
"I have had only one objective in my mind for a long time. Now, I have to think about my club (CASI), but then I'm going to give my best because the final squad is going to be decided by what happens in the United States.
"My objective is clear: I want to go to France."