Being on different roads, and not near each other, you may be hard-pressed to visit, and enjoy, Ernst Tinaja and the Mariscal Mine on the same day. In my experience, it takes at least 2 hours to drive to the mine ruins from any direction. If you haven't explored Glenn Spring, then a loop from the east end of the River Road to the mine, backtrack a bit to Glenn Springs Road, and head up to the historic area is a nice tour. If there's still enough time in the day, you might be able to visit Pine Canyon.
Otherwise, the Old Ore Road makes for a nice day, too.
Another possibility to combine with Ernst Tinaja is the Ore Terminal. I've never hiked to it from ET, but it's part of that complex of trails out there. It's about 8 miles roundtrip to the terminal from the Boquillas road. The ruins of the tramway lie near the trail, and the old ruin sits in the middle of a seldom visited valley with
views of the Sierra del Carmen.