Before I start remember that this is just my opinion. I think by painting the interior you would loose alot of the re-sale value of your RV. If the walls are OK maybe you could just remove the 6" wide border with a blow dryer. I never did like any border that I saw. I have seen some older ones (much olded than yours) painted and I did not like it.
Remember, JMO, you do what you like , it's your home and you do what you like.
Bob

Gypsy,

I've never tried to paint over the wall covering. Never seen anyone who has. If you can take a sample to a good paint store, they should be able to advise you on the best paint to use and how to prepare the wall.

In our 5er the one inch tape covers a seam between two of the panels, the seams match the material that covers the panel so they sort of blend in. Like you stated, the tape is not flat and just doesn't have a smooth look.

The reason for this is the tape also hides the staple heads used to attach the wall panels to the framing of the trailer. These staples work loose while travelling down the highway due to the constant flexing of the walls and road vibrations. In addition the wall panels seams get out of alignment and cause the seams to be uneven which also affects the look of the tape.

The tape can be removed by heating it with a blow dryer, be careful not to scorch the panel covering. Once heated pull gently on the tape and it should come off in one long strip. You need to heat and pull in sections until you've removed the entire strip.

With the tape removed you can add staples to tighten the panels back to the frame to smooth out the seams. These need to be the type of staples a carpenter uses so it requires a special staple gun. I tried 1/2 inch staples using a regular staple gun and they came loose after a few trips. I then used 1 1/4 inch carpenter staples in my air powered nail/staple gun and they have held solid.

I used a water based contact cement to reattach the tape, rolled it with a wallpaper roller and it looks as good as new.

I would have preferred to use new tape but was unable to locate any that matched or even came close to our wall covering.

I only had to do this in 3 spots so far. The other seams are holding. So it's a lot less work than painting the whole interior.

I meant to include, if you paint you probably wouldn't be happy with the look due to the tape would still be there, just painted over. Or if you removed the tape and tried to patch the seams, it would be very difficult to make the area blend in. Plus the patch would probably crack and peel due to the road travel flex & vibration.

I am glad that our rig has no border decoration around the walls. Just about every manufacturer does it.  Our fiver before this one had it and I didnt care for it.
southwestjudy