How successful? Well he would have to do more then a great recruiting job. Since he's a designated Associate Head Coach, much of the teams fortunes will be tied to his coaching as well as Anderson's. As with all promotions to head coaching positions, schools generally look for post season success. How did Holloway get so desirable so quickly? It wouldn't have been from winning his conference or even an undefeated season there. When you win some games in the Big Dance (especially when you are not supposed to) your stock rises rapidly. Again, its post season success.
So in answer to your question, for Van to get any serious consideration for some legit D1 jobs, the johnnies would have to get a few appearances into the Big Dance and win a game or two there.
In terms of Neptune, his return to Nova was as much as done a deal as Brian Mahoney getting the SJU job and most recently Jon Scheyer getting the Duke job. Long time successful head coaches have a pretty big say in their successors.