Ballinstoe is grand, bit of an all weather pitch compared to the swampy natural stuff, biking.ie hire out decent bikes (Deore equpped Treks, always looking brand new, inc helmets). Djouce (just around the corner) is better but you’d need a guide to show you around to get the best out of it. If you’re really keen you could probably get guided by niall (biking.ie owner) in the early evening. If I’d known i’d have given you a loan of a bike and pottered about with you, too late for me to re-arrange stuff to help you out now.
For Running I’d suggest Glendalough, go to the carpark at the lake (signposted visitor centre), Head to the lakes up what’s called the Green rd (it’s signposted, basically carry on up the valley) At the lakes run up the their right hand side (opposite to the side you are on) on what starts as a fireroad up the whole of the valley to the abandoned miners village, follow the trail as it loops up to the left of the valley (starts are a width path with some steps and turns into railway sleeper path over boggy bits)to the top of the spink (odd name for a bit of a mountain) which gives you ace views of the lakes below you on your left and the surrounding hills. Run along the spink and follow the signposts (red as I recall) back down to the green road and back to the car park.