I don't yet see a path to a Rand victory in IA or NH, but neither do I see Trump leaving the race or "imploding" at this point, I think he's in through the spring at least. His presence in the race creates potential openings for Rand if he indeed has a "slow and steady wins the race" plan in mind. Because Trump is not being taken seriously by the media, his dominating the early contests devalues them and puts the primary race into limbo until the "true" front runner emerges. This may give Rand more time to pick up a victory somewhere. If he moves up enough to place at least third or even fourth in IA and/or NH, that may be enough to prove his viability.
By contrast, Trump's presence could spell disaster for Jeb, Walker and Rubio, if they can't make the top 3 or 4 in those two states. As it currently stands Huckabee or Carson could soon move past Bush in polls in both states for 3rd position. It's quite possible that Huckabee, Rand and Carson could climb above Bush in Iowa in the coming weeks or months, with the finish being Trump-Huck-Carson-Walker (Bush in 5th or worse position). In New Hampshire, it could end up Trump-Carson-Rand-Bush (Walker in 5th or worse position). With Rubio not even getting traction, and both Jeb and Walker flailing early on, it could be anybody's race.