With the OP stating that he's looking for the DC options, one needs to take that and other desired options the OP wants into consideration as to how it would impact the price of a new model vs. something a couple years old. Sure you can get a new '18 or '19 with tax credits for about the same price but if it is lacking options that are wanted to get that same price then it really isn't worth the discussion. Personally I like the added safety features in my G1. I was lucky when I found mine, used, with both safety 1 and 2 for the price I was looking to pay. It took several months of looking, but I found almost exactly what I wanted, only the color was not ideal (black). Having the extra safety features might also qualify you for an insurance discount depending on your provider, so that too is something to keep in mind.
Returning to the original question about mileage. That's really a personal preference I think. Of course I'd suggest something with the lowest mileage possible for most, but if you drive a significant amount annually then perhaps mileage and resale value are of little use to you. My '13 had a ton on the odometer when I bought it (93k) and most of those were gas miles, however I did have the extended battery warranty (150k CARB car) and the owner transferred their GMPP to me which gave me warranty to 111K miles which I used twice but never for a powertrain issue. Since I drive 15-20K/year I knew that spending a couple more thousand to get something with half the miles was possible, but how many repairs would I have needed to have to make the choice to spend more make financial sense? So far I've put almost 40K on and no issues that weren't covered, so in essence, I would have "wasted" that money in a sense just to get fewer miles.