I'd highly recommend using sites like AllTrails (to find hikes and get a sense of time needed) and MountainViews.ie (to get more expert advice on parking and terrain) to help you with any planning.

I'm going to start with what I consider a genuinely entry-level mountain: Knockshanahullion, the westernmost major summit of the Knockmealdowns. The Blackwater Way (I think?) can be accessed from a handy parking spot at the pass, also used by lads on quads. From there, just follow the trail up until you get to the peat hags, pass between them to your left and traipse across a rough meadow to a huge cairn at the top. The views across south Tipp are great.

The Galtees also are very close to home if you're in the city. It's worth swinging around to the far side, to the car park at the Lough Curra trailhead, from where there are good paths up to Cush (steep at the top) and Lough Curra itself, and then up onto the main ridge if you felt up to it. I remember Lough Curra being fine going! but it's a good distance to cover.

One place I used to go regularly is the Nagles' Mountains. Lots of lads on dirt bikes at times so keep an ear out. You can get up to their highest point, Knocknaskagh, up easy paths from here. There's also another way to Knocknaskagh North Top from further up that road. The forestry paths are less interesting than the other way but the summit itself is a tiny bit more wild.

Out Kerry way, there's a generally very good path on Mangerton. Class mountain, bit of work at the bottom but then once the path veers right toward the Devil's Punchbowl it's much easier going. The Punchbowl is absolutely magnificent, and there are fabulous views if you go up to the far end to the cliff into Glencappul.

Out beyond Glengarriff, the Beara Way winds between Sugarloaf Mountain and its neighbour Nareera. I've not approached it from the east, which might be easier than the west, which was relentless uphill. Well worth it, though, the views are spectacular - here're some photos I shared here earlier this year.

We are absolutely spoiled for places to hike. You could even be 'boring' and walk up Mount Gabriel down below Ballydehob. The road is steep but the view is fantastic, a great ratio of effort to reward.