I personally last passed this way in 2013. To get to Khentii you have to cross the Onon Gol and both in 2013 and 2016, we used the birvaz. The what? The birvaz is one of my favourite inventions - a floating platform on a pulley system that crosses the river - used by locals with their motorbikes or in this case, by EL with our Furgon van. Tserendorj is the operator and crossing the river this way gives you time to discuss the weather, the state of the Mongolian economy and to count fish.
Or just waiting until it all freezes over.
There's an option for everyone. Our east trips take place from late August onwards. If you're interested in the EL way of travelling, why not have a look at the Mongolia Tour Calendar on my Eternal Landscapes website. You'll find in (almost) a nutshell a guide to the Mongolian seasons and the trips we operate during those seasons.