Longer door hinge screws don't have enough reach on the house side, now what?

[OWC Jamie]

There could be quite a gap between the door frame and the rough in frame. Especially if they originally framed for a bigger door, or someone replaced the original with something smaller and there are rather large shims in the opening. You won't know this without taking the trim board off and looking. I'd try longer screws. Course, I've got a coffee can or two of leftover screws to try.
You could also find a wire or coat hanger or something to fish through the existing hinge hole and explore. It should hit something, but likely insulation will make that difficult.