You certainly are not being too picky about the wall paper and you absolutely should get the repairs done. It is my personal opinion that none of the 3 options you have suggested gives anyone any ability to help. I am sure you already know that you are not getting any money back. You are not going to get new wallboard as this means a complete removal replacement of all walls plus every cabinet on that wall. You are not going to get a 5 year warranty on anything that normally falls under 1 year warranty.
It is my suggestion that you work with the dealer and Winnebago to get the wall paper repaired/replaced in a timely manner without making any unrealistic demands. If you are not able to come to an agreement about how and when the repairs will be done I would contact your lawyer or have him recommend a good warranty lawyer since the warranty claim does not end solely based upon time if the issue has been stated and acknowledged by the seller.