I would be more firm in believing Rob Van Dam would end up in T.N.A. due to the lighter schedule, then he would in W.W.E. again. If he went to T.N.A., he'd only have every other week to shoot their iMPACT! tapings, and he'd likely get a very relaxed road schedule, because he's a big enough name that they wouldn't care.
That being said, I'm sure W.W.E. is in a position to where they'd give him a similar enough deal to just come and go in single storylines that'd last a month, or less.
If what RVDgurl said is true, then his full-time Wrestling days are vastly over as far as I can see. If he's a Family man, and I'm sure he is, his position now is next to his Wife at this time. Cancer is a bitch, and even if it's taken care of, unfortunately it can always return. So until they're comfortable with him being back on the road, away from her.. it's likely not gonna happen.