Rick Jones could have been introduced

Had the series been allowed to continue, it would have been interesting to introduce Rick Jones as David's companion.

Rick could be 18-19, an orphan at an early age, having recently aged out of the foster care system.

It could be a one-or-two-part episode that introduced him. By the end of the episode, the Hulk saves Rick's life, and Rick sees him change back to Banner. There's a mystery that Rick's real parents might have been "important" people.

Rick makes a vow to help David in whatever way that he can, and figures that along the way, David might help him to find out who his real parents are.

So they hit the road together, whether hitchhiking, or on a motorcycle (Rick knows bikes, of course).. Rick frequently uses fake surnames himself (Jasper, Jackson, Jefferson) when they arrive at a new town.

Rick's more "streetwise" skills: con routines, lock picking, petty theft (he's regularly lectured by David about shoplifting, even to survive), could provide some assistance for David that could come in handy, and especially in scenarios where the Hulk's brute strength wouldn't make sense.

Assuming that Jack McGee never sees Rick and "John"/Hulk together, there could be some interesting encounters between Rick and McGee, to throw him off the trail..

"With Great Power Comes Great Responsibility"
Stan Lee, 1962