Defeated Palkia after some more attempts, Geodude had 7 HP left after 2 Dragon Claws, whew... Luckily, no Golbat spawned on my way back.
Volkner was quite easy, the only thing that caused me some trouble in his gym was a Bibarel, that could hit first because Geodude was paralyzed, used Water Pulse, confused Geodude and left it with maybe 30 HP, but I got lucky and Geodude could use Brick Break to defeat it. Now I'm somewhere on that water route between Sunnyshore and Victory Road, Geodude is level 81, same moveset as always.
This isn't really the best place for Geodude, some of the higher Tentacruels can outspeed me, all I have seen being used by them up to now was Poison Jab, but I'm pretty sure they also have Water attacks. And I'm also pretty sure some of the trainers have a Gyarados, which is probably the Pokemon that causes me more trouble than anything else, because of Intimidate of course.
Update: Ok, i managed to pass the water route without too much problems, but now, in Victory Road, i'm having huge problems with PP. All 5 steps, something spawns, and running is a waste of time, so i fight the stuff, but that means i don't get really far, at least not fast. I think i'll first grind to the high 80s (now 84), and then go through Victory Road with repels. Otherwise wild the Floatzels and maybe also the Medichams will screw me up.