Having run the Wicklow Way out and back in 2017, I wanted to add the Dublin Mountain Way to my list. I decided early on that it would be a solo, unsupported attempt.
I picked a day, dorve to Shankill and set off with a supply of food and water. I ran out to Tallaght turned and ran back.
I didn't run with anyone else for any section of the route in either direction and I used only food I carried with me from the start, I did not leave food or drink along the route in advance and I didn't buy anything either. I did get some extra water from some streams I crossed. I saw a water font in Glencullen, but unfortunately it had a "Boil Water" warning sign attached to it at the time.
Editor's note: The Strava map shows that Graham started at the official start outside Brady's Pub, and ran to the end of the trail at Sean Walsh Park, and then returned to his starting point. These are the official endpoints of the trail as described at https://www.dublinmountains.ie/dublin_mountains_way/dublin_mountains_way/. This slightly differs from the GPX map on the route page which starts and finishes at stations, probably for convenience. For the purposes of the FKT Graham's start/end and turnaround points are valid.