While it is obviously helpful to have a car, driving is La Paz is never easy or fun so I don´t miss it all that much.
But anyway, nowadays I walk over 6 kilometers or almost 4 miles each way to do roller ski training at least occasionally.
I leave on foot from where I live at 3860 meters and take a few very steep streets to arrive at the beginning of countryside in 10 minutes. The climb gets steeper and the pace here is about 25 minutes per kilometer. The steep part goes on up until 4200 meters elevation. From there it´s easier with some flatter parts too. The path leads up to 4500 meters on a huge, treeless meadow. Then I need to go down to 4215 meters on the other side, and then climb for a few minutes to arrive at a new, paved road with totally perfect pavement. The downside is that every few kilometer there are gravel sections. The road has not been completed and it´s not been opened to traffic officially, and it looks like it will take years until that happens. There is very little traffic. I would say one vehicle every 10 minutes, or less.
Depending on the wind, in the best case I can train on an out and back loop of 25 minutes. If the wind is "bad", it forces me to use a much shorter section of the road, because it could push me to a downhill with too much speed and onto the gravel. So the skiing happens at 4200 - 4270 meters elevation (up to 14,000 ft). Of course I would rather train much lower, but there is no other place this good, not even close.
Good thing is that thanks to the altitude, the climbing, and the weight of the backpack with roller skis, boots, water and everything, all of the walking counts as training. Today it took 1:28 to get to the ski area and average hr was 121. Skiing was 1:40 with avg hr 133, and return took 1 hour 10 minutes with average hr of 121 as well, including about 30 minutes of jogging. On a good day all of that is easier than it sounds and there is always a sense of freedom in walking up there instead of driving. By car it takes almost 50 minutes to get to the "venue" so walking adds a lot of time efficiency there. Doing hard workouts this way is a bit questionable because it would still require a long workout at the same time.
Even on a lousy day the views are nice.