Back when I first started Halfbiking I used to ride Aurora first almost as a warm-up and then take Arachne out for 2 or 3 flat miles, still working on balance and turns. I found it valuable yet exhausting.
Today I did it just to see if my strength was improving. Legs never complained & I had more than the 11 miles I rode in me.
I held some Oomph back because I had Arachne planned.
It went better than I hoped
Ecbatan 