I can't believe this is even a debate. A less competent version of Ghost Rider (Alejandra) was capable of affecting a country's worth of people with her hellfire.
Additionally, Ghost Rider could just summon a few dozen more Ghost Riders even need be (which wouldn't be needed).
Ghost Rider has taken on tougher foes than Alucard, like Mephisto in his own realm.
Also, just to nip this in the bud now. Alucard's omnipresence wouldn't help, given that hellfire leaves people comatose. And Alucard's omnipresence is dependent on his ability to recognize himself, which won't be possible, because he would be effectively brain dead.