Giving mobile presentations makes you vulnerable to variables that you might think are outside of your control, but are not.
By bringing your own external monitor, PA amp with speaker and wireless microphone, and portable power station for your laptop and external monitor, you will control the variables that are within your control.
Even if you do end up using the display, PA system, standalone computer, and power that the venue provides to you, I still recommend bringing these critical items as a backup.
As I learned more than once the hard way before I started bringing this setup, there are multiple ways a presentation can fail before it even begins due to hardware problems. Even when the venue provides the agreed-upon equipment, all it takes is one dead AA battery in a diversity (wireless) microphone to derail the presentation you prepared and traveled so long to give.
And even if the fault was entirely the venue's, any equipment failure makes you look bad, and may not get you invited back to speak.
There will always be more threats in life that are beyond your control; you have no excuse not to control the few things that are