Just be aware that this is a footpath, not a cycle path. There are some really tough (i.e. narrow, very steep, very boggy) sections that you will be pushing on. Also lots of gravel, forest road so can make up lots of time on there. Would be a fairly big day to do it in one go, but no big deal in two days. Definitely avoid after heavy rain. If you are keen then I’d recommend doing it soon, we’ve had a fairly dry summer here (I live at the base of the Epynt). I wouldn’t leave it much later in the year though, once the rains start here sections of it will turn into a quagmire. There are lots of way marks but they seem to double up in places (showing alternative routes through sections) and can be a bit confusing so would recommend a gpx route on a GPS/phone for navigation.