do you want to find/plan frequencies before you arrive? If you do not have a rf scanner you can lock out (reassign)the bad frequencies, recalculate and get new ones when you get to the new venue.
I like setting up a rf scanner and letting it run several hours at a location and then assigning channels. This works if you have time. Also make sure you add to your data base the frequencies the venue is using. There are many programs that will help you get close, just because the program/scanner says you have good frequencies does not mean you will have a good day! have back up wireless and extra frequencies available.
note:
was at a location 5 days, 9 wireless, everything worked great, last day took a 2 second hit on all the wireless. I have no clue where/what happened.
jd