Decide how long you want to take doing it, then plan the route accordingly.
If you want to do it in a day, then that is possible – but although it touches a few trail centres it isn’t the most interesting.
A 4-6 day route is perfect. It will be 60-80km per day, maybe a bit more on one day and you can go through all the best areas. You can ride Marin, Penmachno, CyB, ClimachX, Nant, Cwm Rhaeadr and Afan.
Cowlyd is good, but Crafnant is better travelling South. Probably avoid the Black Mountain, there are better routes available.
Doethie is a love it/hate it thing. I love it, many people who I have ridden there with hated it.
If you like/want/enjoy flowing trail centres then chances are you will not enjoy it.