Just a heads up for some tough US species. I have had great success with finding Swift Fox sometimes multiples on a single night drive on highway 56/412 from Springer, NM to Clayton, NM especially the 30 miles closer to Springer and on Highway 39 that runs south from Highway 56/412 towards Mills & Roy, NM. This has all been in May and June when I was doing bird surveys on Kiowa National Grassland. I have also had Badgers on two occasions bit at night and late afternoon on and near Highway 39.
I have also been in contact with the Arizona Game & Fish Black-Footed Ferret program, a species I am very keen to see in the wild, and apparently they now have some public event in October when they take people out spotlighting to see ferrets for some multiple day long-weekend event. they also mentioned single nights in July they may take people out. Contact #928.774.5227 and you can get on their volunteer list.
For anyone looking to see Long-tailed Weasel, I had one August ’11 above Island Lake, 2 mile hike, in the Ruby Mtns amongst the large boulders and scree while searching for Himalayan Snowcock. I have seen weasel sightings posted on many birding trip reports from Snowcock searchers so I think it must be a reliable spot. Also Mt Goats up on the highest peaks.