There’s an old expression, “in the powder,” which means that when guests arrive too early. Last weekend a couple party guests showed up two hours early. My house was not yet ready to receive guests, I was still cooking and cleaning, I hadn’t showered yet, and all of a sudden there were people at the door I must entertain. In my case they could’ve spent time walking around my historic neighborhood. Other people must have had this happen to them and heard the excuses: light traffic, easier than expected parking, bringing perishables to the party, etc. How can I get out of this? I love having people over, but I love having them over when I’m ready more than when I’m getting ready.
No host or hostess wants their guests to see “how the magic happens,” and that’s doubly tough when they show up so very early. Sometimes that happens because guests miss the correct arrival time on the invitation.* The Perfectly Proper solution is, as you suggest, to take a walk until the party is supposed to start. That’s tough to do, though, if it’s raining or viciously cold.
You’ll be relieved to know, though, that there’s no obligation to entertain early arrivals. Just park them in the parlor with a “Don’t mind me, I’m in my prep zone," and get back to your business. Deflect any offers of assistance (if unwelcome) with "Thanks, I really appreciate it, but I have my routine already set and I just need to get things done at my own pace."
If you don't mind some extra help, however, toss them an apron and put 'em to work. This can sometimes be more trouble than it's worth if your guests then question how to do what you've asked them at every step of the process, so they can be sure it's done the way you want it. Much better, in Etiquetteer's view, to leave them in the parlor with a magazine.
You can mitigate this kind of behavior in two ways: confirm the time on the morning of your event, and plan to have everything but the cooking complete one hour before the party starts.
*Etiquetteer has had to lecture That Mr. Dimmick Who Thinks He Knows So Much about this more than once. Indeed, his ability to appear up to an hour early by mistake at one annual gathering has become almost an eye-rolling tradition.