If I hadn't received a full magical education. I would finish my training with the elves, and then build a number of Rider Strongholds (Doru Areba being one of them, after I cleaned up the radiation). One major one, and several minor ones, that have good communication lines with each other. Maybe one for each representative species that can be Riders, one for humans, one for dwarves, one for elves and one for Urgals. I would also devote time to learning to control my strength so I could avoid killing with a single punch if I wanted to.
I only have a few minutes so I’ll condense this. I would continue my magical training and I would try to mask the radiation on Vroengard and rebuild Doru Arabea. Then I would re -colonize it and they all lived happily ever after.