Agree with your analysis. Trump is strictly a pragmatist. We will see him "evolve" during the campaign. If he were President, I can see him making deals across the board. Without any real ideological mooring, his deals could be disturbing to many of us.
I don't want an ideologue as President, but his actions should be circumscribed by basic principles and beliefs.
HOWEVER, the good news for conservatives about someone like Trump is that without a solid lib ideology the Dems would oppose him most of the time, so even if he named a judge they liked (for example), in such a case I think the GOP would be emboldened to find a spine and for once the Dems wouldn't want to be too supportive of someone who wasn't theirs. Could be wrong. All we know for sure is that it would not be 100% to our liking. But as I say, if I can get two or three really big wins, smaller losses can be tolerated.