siding issues and front bumper hitch

I recently purchased a 1995 Eldorado from the original owner. It has been stored inside with a cover for two years. I had it outside getting familiar with it, cleaning, waxing, etc. and noticed the siding is "bubbling". I see no water inside so I don't think it's from water damage. I spoke to the original owner and she noticed only a small area bubbling after she took it out of storage. I saw that area when looking at it to buy but felt the price was right even with that condition. Now it seems to be getting worse.
Do you have any advise or information that would be helpful for me? This is my first motor home and hope it will not be too expensive to fix.

I also am looking for information on installing a front bumper hitch (no airbags) for use when launching my fishing boat. Does anyone have any tips on what works best as far as brand, type, etc.?