You found the http://www.burningman.com/preparation/t ... o_brc.html
then if you go to his website he has even more information: http://gwally.com/directions/cat_routes.php
Unfortunately the easiest route Route 58 has construction with complete night closure and big lines for one way traffic of burners who did not know.
Any way you go off I5 Ashland-Klamath Falls, Medford-Klamath Falls, Albany-Bend, Salem-Bend, Portland-Madras and even Portland-The Dalles-Bend has hills You can see the details on Google Earth.
I would suggest I5-Portland-Route 26-Madras, on to Klamath Falls, Cedarville-Gerlach. There is a hill and curves between Cedarville and Gerlach, but no backup if you don't go into Gerlach itself, so fill with gas in Alturas or Cedarville.
Going through Lakeview, a smaller town is nice, because you can stop at Summer Lake hot springs.
I think if you map 80, you will find it as hilly. That route will be very congested. You can do detailed elevations in Google Earth.