Early Arrival for Shows

There are quite a few shows in which the recommended arrival time is well above 15 minutes but my touring plan doesn't account for those. The most it will ever plan for is 15 minutes and sometimes much less (like 6 minutes when the book recommends 30 minutes.) Any suggestions?

Sometimes my step before shows "30 free minutes" or some such- which means it'll work well. If I don't see this, I will remove items then evaluate so I definitely have time. Otherwise I can always just put a break for show time + 30m prior or so