traveling to the US on a visitor visa before J1 starts

We are a couple +2 and supposed to start a post doc in Sep 11 on a J1/2
We would like to enter the US i order to travel in July.
We thought of going to Canada or Mexico as well.
Provided we organize the J1 visa in time.
Is it possible to enter the US on a visitor visa --> exit to Mexico/Canada and reenter on the J1 visa or must we go to our home country ?

Thanks,
E

I'm not so sure but is possible to exit and enter in US, if you a passport.

Check this website, I hope will you understand this information.

http://www.spammer.com/

It is at the applicant own risk both to obtain a visa, and to gain admission to the U.S. as a visitor in lieu of a J-1 visa.