There are at least 3 services that will pick and deliver mail between Penasco and Lukeville. I assume they are all working but I suggest you use Burrito Express, I know they are working. They pick up and deliver between Lukevillle and Penasco I thnk 3x per week. Packages and regular mail. lt is not real cheap but certainly cheaper than just the gas for a couple of runs to Lukeville, not to mention the current sanitary stop. There are, or were, two other services, one at the VFW in the MIrador and at the Salon next to Super Ley. They are in general comparable in delivery and cost.
You must of course already have a USPS box in Lukeville. Quarantine will not effect this.
Burrito Express - Going north on Benito Juarez turn west at the traffic light at the BB Stadium go to the first street to the right. It will be on your left hand side of the road in one block. . Big sign, cannot miss it. Open like 9 to 4, M-F or so right now. Hours have changed so not sure.