Asklemmy

Hiking is the obvious one, but to give myself a reason to get out there more I've been trying to get into bird watching and photography.

It depends on how active you want to be. Hiking on flatter, less challenging terrain on shorter routes is an obvious choice, but if you don’t need to be exercising then you could look at touring gardens (and butterfly gardens!) or painting or drawing landscapes.

Oftentimes I find that my own sense of restlessness comes from a feeling that I’ve been consuming too much, in the form of entertainment, and not creating or expressing myself. You don’t need a lot of equipment, just a good sketchbook to start off with.

Trail maintenance. I spent over a decade doing work on neglected trails in western NC. Hours upon hours of hiking, weed eating, sawing, taking, etc. It was more exercise than biking the same trails.

I'm struggling with the loss of the mountain biking I've loved for a long time. I'm trying various changes out to keep some biking in my life. I'm biking more slowly and for diminished distances. Also my wife bought me an emtb that I've been trying out on the trails. Less fatigue means I'm .asking less mistakes while out.

I hope you find an outlet you enjoy. The loss is truly life altering.

I’m biased but birding. Just go to a trail or anywhere with some binoculars and some apps (Merlin bird id and eBird) and that’s it. Just walk around enjoy nature pay attention to the little things. You will begin to see just how beautiful the world is

Rowing. Outdoor exercise you can do sitting down. Plus you get a strong core. Join a rowing club - most are for rowing skinny "slidey seat" boats, but there are also various fixed-seat traditional rowing boats, eg whaleboats.

Swimming/floating in a lake

Fruit picking

Fishing (there are also some places with bounties on invasive fish and other water creatures)

Amateur astronomy

Geocaching

Rockhounding

There's trekking, camping, exploring, and gold prospecting. Or if you really want to get busy you could always build a cabin in the woods. Age has made me a lot more risk adverse like you. I'm contented with just sitting and cooking around the fire once in a while these days.

Backpacking is a fun one, but it can be expensive.

Hiking is the first one that occurred to me (and an activity I enjoy). You can still get lost, twist an ankle, etc, but it feels way less likely than bombing down a trail on a mountain bike. (Seems like I keep hearing about broken collar bones on mountain bikers.)

Orienteering can be less physically risky and demanding, but still challenging. There's probably a group not too far from you, check out meetup.com maybe.

Not free but outdoor rope courses are a lot of fun, thrilling but with low chance of injury.

Geocaching can be fun. I don't do it a lot because I get frustrated easily, but I've found a few well maintained caches in state parks and that keep me going. Often, the ones at the state parks are placed in locations that will bring you to a place that is special to that park, off the beaten path and safe. I can't remember the park, but one cache I found at a state park was next to a small historical marker, deep in the woods alongside a river, but the marker indicated that it was a meeting place between Native American tribes from the fur trading days.

If you live near water, kayaking can be an incredibly immersive pursuit in nature that doesn’t really tax the body (unless you want it to)

Trail running is another one of my favourite things to do, but while much safer than MTB still can have some risks… minimal though, comparatively speaking

Rock Climbing is a sport that gives you a lot of control over risk. Once you understand the technical safety aspects, you can evaluate risks of a particular course of action.

Climbing mellow routes with a top rope is quite low risk.

It’s a longevity sport, at crags and gyms it’s pretty normal to see people over 50 still at it.