If you disregard the gravity of other objects, then there is no upper limit.
If you toss a ball up with one hand so that it arches over and you catch it with your other, you can think of it as being in an elliptical orbit that happens to intersect the earth's surface. If all the mass of the earth were compressed into a point at the center, and if we could ignore relativistic effects, then the ball would actually complete a very long, skinny elliptical orbit. But, because in real life this orbit intersects the earth, it's not much of an orbit, so we call it a suborbital path.
So, that's a very low suborbital path. But earth's gravity, in the simple Newtonian approximation, goes to infinity. And it sounds to me like you are interested in the really simplified case where we ignore the rest of the solar system. In that case, if you start out below escape velocity, you will come back. The closer to escape velocity you start out at, the farther you go before you start to fall back. And there's no limit to how far that could be. If you leave right at escape velocity, you keep slowing down forever but never reach a stop and start falling back.
If you want to go into a full orbit that doesn't intersect the surface, you have to start by launching up and then turn and accelerate sideways. If you have no acceleration after you leave the surface, then you are already on an orbit that intersects the surface, so you can't help but hit it on the way back too.