When applying to a VAP position at a SLAC should your materials look substantially different than you would if you were applying for a TT track position? If so, how might you tailor them?
The general answer from my experience on an applicant and search side for VAPs is no.
That said, some things are worth noting. First, there's a real possibility a VAP at some institutions comes with near zero research support. It's hard to decipher whether this would be the case, but if the job ad says absolutely nothing about research, then consider it mostly a teaching hire. In any case, most VAPs are not as well funded for research as tenure-line faculty. Thus, temper down emphasis on any costly research activities in a cover letter. Otherwise, when I've been a VAP search committee member, I always tried to figure out if an applicant were using the VAP as a back-up. Yes, we all should aim for tenure-line. What I wanted to know was whether the applicant had seriously considered how working for my institution for a few years could be a viable factor in their developing a successful career. So, I recommend specifying how a VAP fits into your long-term career goals in the cover letter. If you can custom tailor how the specific VAP fits, all the better. Good luck!