I think the turnout and response to this rally tomorrow will give us a general idea of how effective his disinformation campaign has been. Up until now his most ardent supporters haven't really had a "safe space" where they can gather and show support for him like his opposition have had in the major cities.
If it turns out that the bulk of his election support were basically just folks who vote "R" no matter what and anti-Hillary voters then it will be reflected in lower than normal turnout to this event since those people should have been satisfied with the win. If it's a huge turnout of enthusiastic supporters then we're in for a very long fight for the soul of this nation.
Be prepared for a crowd (never underestimate the power of cult personalities), and even if it's only moderately large, be prepared for Trump to tout its size as justification for his decisions for the weeks and months ahead regardless.