Don't worry if you have to check in late. We have had to do it before and we are not usually the only ones checking in. We just pull in the site, plug up the electrical and go to bed. Everything else can wait until morning. If your set-up is more involved, checking in at a value is always good option.
The reason we try to avoid the late nights is my feeling, whether valid or not, that we sort of get "whatever is left" site wise.