Traffic?
I am also having a NJ/LI wedding-- as for traffic I commute NJ/Queens everyday-- the best bet is to use different routes meaning the Cross Bronx is horrible but often the most used route-- think about using the Major Deegan to the Triboro---that goes into Grand Central which turns into Northern State--- just an idea-- we do this commute often and this is a little better but Fridays are crazy either way--you have plenty of time so 'convince' as many people as you can to take the day off--especially important family members !!!
Hope that helps
Laura
