The City Nerd channel on YouTube and Nebula discusses this issue a LOT. Trains are by far the most cost effective method of transporting large numbers of people and goods.
Here’s a video discussing costs of car use
Here’s one on the cities with the most affordable housing and transportation costs. As he explains housing and transportation costs are directly linked to each other.
Check if your area has a Weed Warriors group/organization. They go around removing invasive plants that are smothering native plants. I find it fun and get a satisfaction of having done something nice while exercising.
If your area doesn’t have that, there’s most likely opportunities to volunteer with hiking trail maintenance at nearby state parks. Or just go hiking, start small and bring water!