Last minute parties can be the best at times. I think it's easy to set up a style of hospitality that caters to dinners on a whim. Often, people think things have to be perfectly planned. Really I think if you set a few basic principals in place it's easy to throw together a lovely meal and not be overly stressed by the planning and preparation.
Keep the word simple in mind as you plan and have a few go to ideas. Calzones are easy to make ahead of time, I learnt this from B, and fun to eat! I bought some pizza dough from Trader Joe's, sautéed some vegetables with pepperoni and some spices put them in the dough added cheese and threw them in the oven. You don't have to be quite so lackadaisical in your approach if you're the type that needs recipes and exact measurements- embrace it and find those go to recipes. I'm comfortable with a bit of this and that and optimism!
Do one side dish (it's easy to go crazy, quality not quantity!), a salad is always a good choice. Bread, unless it's part of the dinner as it is in calzones, and a simple dessert. My go to is Trader Joe's brownies and vanilla ice cream. Easy to whip up, warm and delicious!
The best part about all this is that B does the exact same thing and I learnt many of these tricks from her. She's able to do this making everything gluten free, dairy free, and generally without eggs. I try to cook accordingly when she's around, and also to learn from her when I visit. So if you have allergies don't shy away from entertaining, embrace them and make something delightful! It is possible and can be made easy with practice!
A house should be a place where people can come and feel at home, not a museum to look at. Chairs should be comfortable to sit in, plates made to be broken, and though I love a clean home- a mess means life gets lived! This is my weakness, I always want the house -or apartment- spotless, that tends to be more stressful than helpful, so figure out a healthy level of clean for entertaining but don't go overboard or simplicity goes out the window and stress goes through the roof. For me planning and preparing ahead helps me to be present when people arrive. Just figure out what works and then enjoy the evening!