When I am doing stuff in my city I do everything by bike. For longer trips, for example when I'm visiting my parents I travel by train. Those are pretty much the only ways I travel besides walking.
For me this is everything I need. In my opinion traveling by bike is the nices way to travel relatively short distances. You have no traffic, don't have to wait for busses or trains and it's by far the cheapest way to travel.
But trains are also a very nice, at least when they are not completly full. You have enough space, you can work or study. In generell you can just do whatever you want in a comfortable seat.
I'm new here and I'm not sure what defines simple living but I usually go by foot around town.
Distances are relatively short and it doesn't take long to walk around. The cities in my country are very walkable. When going out of town I prefer the (dilapidated) train network. With my discount card I can ride 400km in around 6 hours for as little as 10$. I'm terrified of driving and I don't want to bother with maintaining a car, not to mention the environmental impacts. If I really need a car when I'm overloaded with groceries, I order a cab but that's rare.
I am also bound to using a car due to where I live. Fortunately I work from home, and most of what I need is close by so I don't need to use it too much.
Same. I ride my bike places when it's feasible, but I live a few miles from anything. A bike ride into town implies at least 20-30 minutes of sweating, which means I have to drive my car more often than I'd like. I have a plugin hybrid that gets about 30 miles without burning any gas, and that gets me most anywhere I commonly need to go, so there's that at least.
Walk. I walk a lot... well not since the last few days since I broke a bone, but usually :p
Public transportation. here in Paris we have a lot: buses, tram, metro, train.
Taxi or Uber when we really have to. My spouse and I have not owned a car in over 20 years.
We have also refused to travel by plane since the early 00s. Be it for personal or pro needs.
Walk has had the most crucial influence: it helped me get back into shape like nothing else did, both physically and mentally. A few years ago, I was not walking at all. As a matter of fact, I could barely walk a few meters before having to rest, my health was a mess. Nowadays; I will walk every single day for 8km or more.
I ride my bike for all day-to-day stuff. ie. to and from work, to shops, to visit people, and basically everywhere else. For longer distances I use public transport.
I have never owned a car, and I'm getting old enough that I'm increasingly confident that I never will. I value the principle of 'do no harm'; and my dislike of cars seems to go stronger the older I get. That said, I understand that different people and places have different needs. I'm not trying to talk you out of using a car if that's what you do.