You're so right about getting there early. Especially because roads around the around the race venue are probably closed for the race already, traffic is redirected, and whatever mapping device you're using probably doesn't know about it. I nearly missed my last 70.3 because my wife's boyfriend kept hitting dead end after dead end!
Oh gosh yes! The roads are always closed and often you have to walk a good distance to check in. I’m glad you didn’t miss your 70.3, but I am sorry it was stressful. I have been in that situation too and it’s not fun!