Fear not! I will help you out!
I suggest you to run an Impish(+Def,-SpA) Hippowdon since Bold(+Def,-Atk) will just decrease the power of your earthquake. If you are taunted,your only move is earthquake.So,try giving it an impish nature.Change its EV's to 252 HP / 4 Def / 252 SpD.Hope this helps.
Now,as you can clearly see,jolly clearly decreases your SpA.So grass knot would be quite useless.Have stone edge for some ice coverage and power.
It needs a lot of improvement.Here's what i use.
EV's:252 SpA / 252 Spe/ 4 Hp
- Grass knot
- Signal Beam
- Nasty Plot
Nasty Plot allows Pikachu to boost its already great Special Attack and go for a sweep.Thunderbolt is the best stab it can get.Grass knot for some coverage against ground types.Signal beam again for some nice coverage.
Hope this helps! Have fun using your team!