For us, family of 5 with 3 teenagers, we go through a ton of food.
We found a few places around us that don't deliver but will do curbside pick-up and put the groceries in the trunk. We do that for most of our staples like milk and eggs and produce.
We also order restaurant deliveries about once a week, more than we normally do.
I also order meats and seafood delivered on line, just got in 15# of Cajun sausages and shrimp. I also go to our local seafood store occasionally when it is not crowded. I probably haven't gone to the grocery store on over 3 weeks.
I bought a bunch of flour and yeast ahead of time so I am making fresh bread a couple days a week as well.
And most importantly, we have a few liquor stores that also do curbside delivery!
I'm also the designated shopper. My wife hasn't left the house for more than short local walk in weeks...So, to answer Mrs. Peel's questions:
getting occasional restaurant deliveries to stretch the reserves (or just for a refreshing change of pace)?
We haven't bothered with delivery yet, but I been picking up take-out about once a week. Partly for the change of pace, partly to support the local restaurants that we really want to have still in business when things return to normal
getting groceries delivered (if they have that in your area) to add to supplies?
We looked briefly into grocery delivery, but the backlog was huge. We'd have been waiting a looooonnnngg time
going out occasionally to grocery shop... again, to top off your food supplies?
I usually go to the grocery store once a week, early in the morning. Most weeks I'll make a second trip out to Walmart or Home Depot. That's about it. I kinda like the opportunity to get out, even though shopping has become much more difficult.
staying in entirely, and just living off what's in the house already?
I think we could get by fine for three weeks without resupply, but the natives would get restless as the favorite foods run out and we're left with everything else. I know, first-world problems...