We've only been open in Oregon for two weeks. I haven't been to a grocery store since early March (we do pick-ups), do take-out from restaurants no more than once a week, restaurant delivery no more than once every two weeks (but mostly because the apps are terrible for restaurants), haven't seen another person besides my wife in any context, including distanced/outside. I would like to go visit a restaurant's outdoor set-up, but our county was already not actually meeting its benchmarks when it opened, and cases have continued to rise. The message from the governor has basically been, "you're allowed to go to restaurants or do leisure travel now, but don't, or we might close again. Which, paradoxically, makes me want to get in a couple of outings just in case that happens.
But I've also been to liquor stores, the UPS store and my wife had a short outpatient surgery. She also goes to our farmer's market which is outdoors and capacity-controlled/distanced.
As far as mail I sometimes try to quarantine stuff for 24 hours (packages, especially from Amazon) but really just opening it and disposing of the packaging and washing your hands is enough. We'll wipe down groceries a bit. Don't wash produce any more than usual.
Even if surface transmission was a big risk the answer is still just to wash your hands constantly, and always before eating, and don't touch your face.