It's a breeze
However, I forgot that I bought a polypore staff upon reaching magic level 80.
And I planned to use that of course. On top of that, I discovered the lectern allowed safespotting (and no I didn't read a guide for that). The combination of pps and safespot made me breeze through that fight, and I can now honestly say Dream Mentor is easy. And then I was fed up with quests for a while and decided to focus on my "all skills level 70+" goal. I cheated a bit by buying a lot of silver bars so I could start crafting tiaras immediately, and not having to mine all that silver in the diy-way. I wanted 70 crafting of course, but I decided to go for level 75 because that unlocks the slayer ring.
Finally I got that level (yay me) and immediately I went to Sumona to see how many points I needed to learn to craft a slayer ring. I ran 100 points short, so I took a slayer assignment from her. First I got elves, which isn't so bad in Lletya because of the prayer altar upstairs.
Then I got iron dragons. Not feeling up to them, I am now fully immersed in the new Runespan. After all, my runecrafting level also needs to be 70+, so that's a good excuse to avoid Iron Dragons, right? Like lots of other players I immediately went to the Runespan upon logging in, and in once evening I gained 3 runecrafting levels (66 - 69). And I like the runespan too! I'm thinking about camping there for a while.