Hiking in Austria mountains

It's been many, many years, but we stayed for a week in Schladming in late April 2000. Our condo room was mostly a base from which to do day trips. One day involved a short hike to a waterfall above town on a well-maintained trail with a car shuttle to and from the trailhead. Most other days we traveled to other places, like Saltzburg, but other hikes were available. I know the area also has multi-day, hut-to-hut hiking, not what you’re asking about, but there is variety. We were in Schladming in off-season, between ski season and summer, and many shops were closed, but it looked like there were outdoor stores that should stock hiking gear, clothing, and supplies, if you didn't bring everything you need from home. We didn't realize or appreciate at the time that Schladming is a major World Cup ski site, so it’s busy in winter.

As mentioned in other posts, hiker's paradise is the town Seefeld in Tirol above Innsbruck, i.e. elevation 4000 ft, providing 100+ hiking routes of different length and severity. You shouldn't have difficulties finding hiking trails appropriate for your physical condition.
https://www.seefeld.com/en/summer-3/walking/hiking-trails

Seefeld can easily be reached by a scenic train ride of 36 minutes from Innsbruck in case you prefer to stay in the city.

Check out Alltrails.com for searchable hikes based on interest, duration and difficulty.

If your knees are good, the hike down from the Jennerbahn Station to the parking lot is listed as "moderate". That would be pretty picturesque.

Nearby Ramsau has an AMAZING short hike up through the Wimbachklamm waterfall gorge. I will say that the very first part from the parking lot (which fills up early) up to the gate is the hardest part of the hike. You do need some coins to buy an entrance token from the machine.

I love that you guys are rocking hikes in your 80s. Well done. "A body in motion tends to stay in motion"

Is there a particular place/Bundesländ you would like to visit and time of year? Moderately challenging as in 5-8k without too many slopes? Stops for a drink and or lunch?

Igls, Lans and Vill are Innsbruck suburbs, easily reachable in 15 minutes by urban bus. They are on a sort of mountain shelf, way higher than the city, so they offer relatively flat hikes in wooded areas.

Thanks so much for your suggestions! I think that we’ll try to make Innsbruck our home base and plan to hike in September or early October! So many great suggestions!

If you're interested in the Innsbruck area, consider Seefeld. It's a beautiful little town of 4000 souls, little higher elevation, more tucked back into prettier mountains with a lot of easy infrastructure, lifts etc. Plenty of hotels, restaurants, etc.

Innsbruck is a city of over 300,000. It sits in a wide valley. You can access high country, but it isn't as pretty as Seefeld. Innsbruck has a nice center, but it is a city. I had to ward thieves away from my bicycle outside the supermarket near the train station. It's an industrial city, with quite a lot of light and heavy industry ringing the old core. It's not a bad place - I've stayed or been through many times. But it's not a gorgeous little Alpine village area like Seefeld, Zell Am See, Mittenwald, Shruns, Tannheimer Tal (my favorite), etc.

Also, and meant absolutely genuinely, wonderfully inspiring that you and your husband in your 80s are still getting out there and moving around in our big beautiful world. You guys are awesome.

Thank you for your suggestions and wonderful comments!

Is April too early for hiking in the Seefeld area?

Check the seasonal running dates/times of the Bergbahn/Seilbahn. Some may be closed in April (Nebensaison). I walked around the Wildsee and down from the Katzenkopf after a knee replacement. An easy walk.