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...