Rather than catching the bus from El Chalten to El Calafate we chose to combine the journey with a visit to the Petrified Forest. We left El Chalten by car, drove to the La Leona roadhouse where we could have a coffee and use the bathroom and then we joined some others, a driver and guide and went to a site on private land. We parked right on top of a massive escarpment and looking down it resembled a lunar surface. Our guide Christian was very informative and for the next two hours we walked right down to the valley floor and en route he pointed out a couple of dinosaur bones and some very large petrified trees dating back about 100 million years. We were given a very adequate boxed lunch and sat amongst the strange formations before starting the walk back up.
We found it a fascinating way to spend a few hours. A couple of hints, use the bathroom at La Leona because apart from that you have to find a piece of rock to hide behind! Obviously sturdy shoes and we found our walking poles were quite useful to navigate some of the narrow or steep paths. If you haven't got one of your own, you can borrow one. We did have some people on our tour who were not that fit but they took their time and did not have any issues.
We were then transported on to El Calafate and taken to our hotel. This trip can be done in reverse.