I like to scout from a Good distance 300-400yds away with the truck should be alright.
Get out andwalk a little,Take along your binoc's,But if you know the bird's are in there walkin early before roosting and sit down and listen.
Then the next day use the binoc's to locate them on the Roost.
As long as you keep a good distance,You should not have a problem with spooking them.
I wish you Luck