There are a few options. I would create the plan and the tasks as
normal, entering the proper estimates, predecessors, etc. and see where
your Conference Start Day ends up in your plan. If it's late, you know
how late you are and you can investigate tasks to see where you can
"crash the schedule" (cut tasks or add people, etc.). Then after getting
the plan where you want, as you update your plan each week, you'll see
exactly where you are and if you're in trouble or not. The earlier you
know tha...