IMHO, staying neutral in the presidential race and not doing anything either to help or to hurt Romney, and just focusing on other races and projects in 2012 is the way to go.
If Romney gets elected president, and I think he probably will, then our hopes for the near future depend on the GOP turning on him. If that happens, Rand will be in the best shape if he is seen as someone who was never part of the Romney camp, but he comported himself with class. If it doesn't happen, then it won't matter because Romney will just get the nomination again in 2016 anyway.