So, as I suspected, the Planet Red Hulk storyline is only a two-issue diversion rather than any attempt at a full-on epic like the original Planet Hulk. Thunderbolt Ross is back on Earth by #36, as evidenced by this preview.
Looks like the new bald M.O.D.O.K. is ready to make his move to exact his revenge on Ross for jumping ship and fouling up the Fall of the Hulks master plan from the Intelligentsia, and he's utilizing the unbridled power of Zzzax to make it happen. This'll be one hell of a fight, by the looks of it.
Check out these preview pages from Hulk #36, due out in July from Jeff Parker and Patrick Zircher.