To paint or not to paint
Life is a Journey not a Destination. In other words if painting makes YOUR trailer look good and pleases you then enjoy the process or the journey of learning to do something you haven't attempted before. Those 70's Airstreams were't perfect when they came off the line and there is a lot of improvements to be made.
However many of us have bought our 'Streams where the PO did something that wasn't of the highest quality or was shodily repaired. When that happens all the collective wisdom of these forums can't tell you how to get her back on track.
For what it's worth.