My parents are not ready to leave their home. Ideally it would be a place with other social folks. Meals seam to be the hardest to plan and get ready - and eat by themselves. If there was an assisted living place that opens dining up to non residents - ? Restaurants can be hard night after night - again no social interaction and people do not seem to have patience with elderly diners....
As others have said, a lot of senior centers have noon meals and meals on wheels is a good option and provides some social interaction with the people that deliver. Most will keep a good eye on your parents too as they see them everyday and will notice changes in their life if they come up.
AL guest meals are usually in the 7 to 9 dollar range in my experience and I think they have to know a resident there. Love my mom's AL as they have a separate bistro open to the public. Soups are $1.50 and sandwiches and salads are $3.50 - all good and fresh. The woman that runs the bistro is an angel, so good with the elderly. I think it is a model that all ALs should follow and I hope you can find a place like that. They do close at 2 though, so evening dining is not an option.
Many Senior Community Centers offer a hot meal at noon every day. My aunt ate all her lunches at her small town center for several years. And then you can also participate in activities such as card playing, jig saw puzzles, and book discussions. But if all you want is the meal, that is OK too.
For restaurants it is often better to go at non-peak hours. Having coffee and toast at home and then having a mid-morning "brunch" can be more relaxed than contending with the working crowd on their lunch hour. Late afternoon can be better than peak time for dinner, too.
Meals on wheels is another option, but I think I would tend to "save" that for when your parents can't easily get out.
I hope you find some good local options for your parents, Beth. And you are right -- it is not merely the cooking. It is the planning and the shopping and the storing leftovers that becomes too much. Tell your parents they are eligible to retire, and help them find fun places to eat!