I am afraid that you are missing the point. He (or she) would like challenging content at the level they are. As well as have a chance at improving gear at the same time..
But see, that's the problem... it's either/or.
You cannot improve your gear without increasing the level of your character and thus decreasing the challenge of the content.
You have to make a choice between the two.
You can experience the content without the challenge or you can have the challenge without the gear.
The scenario you're trying to describe isn't feasible within the framework of the game.