For gravellers in the Dublin/Wicklow area, just some updates on my explorations over the past year.
There is a really good logging road, about 8 km over Sorrel Hill, near the Blessington Lakes,and another 7 km loop of logging roads in nearby Ballysmutten, which I've ridden since I posted here last. And to get there, there's a nice gravel road through the Glenasmole valley past Tallaght and another nice (but hard) gravel road that links the Ballinascorney and Kilbride roads. It's a roughly 60 km loop. Tough, with lots of climbing but good fun.
I hope my friend doesn't mind if I post the route that we rode on strava.
Second favourite would be following the Wicklow Way route, starting at Kilmashogue, going over he top of Three Rock down onto Ballybetagh road, then over the next range of hills (the top is call Prince William's Seat, you can also follow the Wicklow Way but that involves a bit of hike a bike) and down onto Glencree Road, then follow the Wicklow Way across the valley and do the logging roads on the other side starting at Crone Woods.
Here's the route, roughly.
A bit further afield, I've recently ridden the fire roads at Balinastoe where the mountain bike trails are. They deposit you over the lakes at Lugalla, you can then take a left and then a right onto the Wicklow Way, which in this part is nice dirt road, which will take you near Lough Dan overlooking Roundwood. One interesting discovery I made during the year is that there is nearly a dirt road that connects this road with he military road, across the southern side of Lough Dan. Astonishingly beautiful but you have to walk for a bit where the dirt road becomes a walking trail called Logan's Way.
For short spins, Hell Fire Club and Massey's Wood and Cruagh Woods are a good combo.
Finally, I'll just repeat my opinion as expressed in the post above earlier this year. For me, at any rate, gravel riding should not shade into mountain biking, because then you have to use bike that is inefficient at road riding. So for me a good gravel ride involves decent roads kms as well as gravel. Use robust and wide but mostly slick tyres and pressure should not be too low. I favour 50-60 psi personally on my Cannondale Slate.