Everything about a bike race happens in a field, and the field is always further from sign-in than it looked on the map. Sign-in closes 30 to 60 minutes before your start. Staging fills before that. A warm-up worth doing takes 20 to 30 minutes, and it comes after the drive, after the wheels go back on, and after a breakfast that needed to happen three hours ago. Ready Time runs the morning backward from your start, so the alarm gets settled the night before instead of at 5am with a floor pump in your hand.
Getting to a running start line takes shoes. Racing a bike takes a car, a rack, wheels that came off for the drive, a pump, and a number pinned flat enough that it doesn't flap. Budget it honestly and that's twenty minutes to unload and build, twenty-five in the sign-in queue, ten more with the pump and a last look at the brakes. Most of an hour before you've turned a pedal, and it's the hour that vanishes when you plan the morning around the drive alone.
Set the deadline to your start and the steps land on the clock behind it: breakfast, kit, bottles, drive, build, sign-in, pressure, warm-up. Do it the evening before, while the bike is clean and you're still honest about how long the drive takes. Pad the parking, because race parking is a field and the walk from the field to sign-in is longer than the map suggested. The warm-up is what disappears when everything else runs late, and it's the step that decides how the opening ten minutes of the race feel.
Two to three hours before your start for the real meal, which is what turns a 9am road race into a 6am breakfast. Stick to what you eat before a hard training ride: porridge, rice pudding, white bread with jam, nothing that sits heavy or takes much digesting. If your start is late morning, a top-up 30 to 60 minutes out, a gel or half a banana, keeps you from lining up hungry. Early starts are the awkward ones, and most riders take a smaller breakfast over skipping it.
Most racers do, and it tends to beat complete rest. Thirty to sixty minutes easy with a few short efforts, say three at thirty seconds near race pace, keeps the legs open without costing you anything the next day. It's also the last honest chance to find a dead battery, a soft tire, or a rubbing brake while a shop is still open. Ride the day before, then give the evening to dinner and packing.