sdagro --
I have the "ladder mounts" for my Flagpole and they work great! To answer your suction cup question, for LSU football weekends, LSU requires that generator exhaust be discharged above the roof line of any RV. When I owned a Tracer Executive 30 foot travel trailer, I used plastic "suction cup" hooks to support my Camco generator exhaust tube. I attached those suction cup hooks to the wall of the Tracer. The suction cups left rings on the gel coat that could only be removed using wax.
For the Damon Astoria diesel pusher I had the last three years, I attached those suction cups to the driver side window to support the Camco exhaust tube. The suction cups left rings on the window which could be removed with Windex. This fall with my new-to-me Newmar Ventana LE I'll also attached the suction cup hooks to the driver side window to support the exhaust tube.
Given my experience with suction cup hooks leaving rings on surfaces, I would not use the suction cup mounting for a Flagpole on the nice paint finish of my Ventana LE. Does your Dutch Star have a rear ladder? If no ladder, I'd recommend using a receiver hitch flag pole holder such as this one from Walmart -->
https://www.walmart.com/ip/New-Hitch...10090302008005