1. Am a right to be concerned that if they fix this problem, it could surface elsewhere? If not in a years time, perhaps in 2 or 3 years when it's out of warranty?
2. What would cause this electrolysis and how can it be prevented?
3. What are my options in dealing with the RV dealer that I purchased it from? Ask for a full refund? Get another camper? Get them to fix the one affected area and pray it doesn't happen again?
1) Just fixing the symptom, corrsion, won't fix the problem. Any fix by the dealer would require an explanation of what caused the problem to begin with.
2) Dissimiliar metals and stray current are the 2 most common sources.
3) The rash on your siding should be relatively close to the source of the problem. If they remove some siding and identify/fix the source of the problem, I'd feel confident in your camper.