If Trump wins the presidency he will be in a unique, somewhat precarious position.
He will have a hostile Congress & Senate. The Democratic hostility will be obvious, yet the Republican opposition will be the more dangerous & unpredictable. Boehner & McConnell will not be his friends.
This leaves Trump with one support group, a powerful one - the people who elected him - the American people. Trump has made a bunch of promises to these people on immigration, trade, jobs, the Iran deal, etc. They expect positive results.
If Trump reneges on these promises he will lose his public support fast. If he tries political double talk, the public will recognize it. If he fails to produce on his promises he could be the earliest lame duck in history & a shamed one-term president.
For this reason, & because I believe Trump is an honorable man, he is bound to the positions he has taken in the campaign. Further, he is too proud to be in the league of political liars & losers.
I agree with what you said and would add that Trump would use the power of the bully pulpit in a way that none of the others could.
He will have already taken on, and won, against the democrats, GOPe, and the media.