So, by accident of circumstance, I ventured through the park the low-carbon way, without the RV, snowmobile, hunting rifle, BBQ, plastic chairs or anything else. I was amazed the park had dual carriageways with overpasses for the traffic. I found my time in the park to be slightly frustrating and the time in the greater area more satisfying. The hordes of RV tourists and their eagerness to photo anything that moved was probably the thing that made it not so fun to be in the park.
I should say that bicycle + Yellowstone is a very good option as you can camp anywhere in the National Park campgrounds with no expectation to book. The RV people have to book aeons in advance and can't just casually turn up before dusk to get a pitch.
I am sure that cyclists annoy motorists on the park roads, it is apparent that you are annoying others - queue of traffic behind says that. But I am not sure motorists are aware that they might be a 'yahoo' of sorts. I am not sure that being a 'yahoo' is actually that wrong, perhaps it is the regular RV that is more insidious, as there the RV owner has taken everything to the park that cyclist types like myself have gone to the park to escape! TVs, motors, outside music - all nice things but nuisance and unnecessary too.
Obviously the park should be closed to all traffic that emits emissions, to make the place a nice drive for Tesla owners and cyclists. Then we could have lots of people driving their ICE car to the park to then hire some electric transportation. That would be better income for the snowmobile operator types.