May purchase Roadtrek with odometer in kilometers

I don't think it would be a deal-breaker, at least not for me. 100 km ? 62 miles, or for quick close enough estimations, 3 miles is 5 km and 6 miles is 10 km.

If you're going at a steady speed, you can also figure time. For 60 mph, this is trivial; one mile takes exactly one minute. Or you can rely on the mile markers along the road, or (in most states) exit numbers on interstate highways, which correspond to the mile markers.