Ideas for mains (that you can prep mostly ahead and just bake/heat before the meal)
-Stuffed peppers with tomato sauce
-Chicken marsala
-BBQ beef short ribs (expensive but easy)
-Baked mac and cheese
-Brisket
Ideas for sides (depends on your main, obviously...)
-Roasted acorn squash, or baked sweet potatoes
-Roasted tomatoes
-Roasted cauliflower
-Grilled mushrooms
-Rice/quinoa/pasta/couscous/bread
Salad - I'd decide what dressing you want, and base the salad around that. My new favorite is a Greek yogurt one I found in the refrigerated section, Opa is the brand I think. It's a feta dill dressing and it's tangy and delicious. You could do that with just green leaf lettuce, cucumber, tomatoes and red onion. There's also an Asian sesame vinaigrette I like to make (super simple - literally sugar dissolved in warmed vinegar with salt and a healthy amount of pepper, then sesame oil added at the end) that would be good with romaine, green onions, shredded carrots and slivered almonds. And I always love a good balsamc vinaigrette on a spinach salad with goat cheese, fruit (apples, pears or strawberries), and some kind of nut.