Unlike in its earlier poll, Rasmussen did not offer voters the option of staying home, which at that time 6% took. However, it still offered them the option of voting for a hypothetical Third Party, which 15% took in both polls.
You can only get to the poll's “demographic details” if you are a Rasmussen “platinum subscriber.” Trump's share of the white vote has risen to 48% vs. just 33% for Clinton. Support for a Third Party is substantially Republican and "Other" (Rasmussen-speak for independents). So presumably the bulk of this (say 10 percentage points) will migrate to Trump if there is no Third Party and the Conservatism Inc. temper tantrum subsides. But that would still only put him in the 2012 Romney white share range—a measure, let the record show, of his relatively greater appeal to non-whites.
Which in turn suggests that, once Trump does get "started on" Clinton—especially the extreme Treason Lobby position she has, in default of effective GOP opposition, taken on immigration—we could be looking at a Reagan-type landslide.