Could it be formaldehyde off-gassing and not mold/must? RVs have a lot of materials that have formaldehyde in them and some have more materials with formaldehyde in them than others. Some people are more sensitive to the odor and off-gassing can cause various symptoms such as eye, nose, throat, and skin irritation, coughing, wheezing, and allergic reactions. The level of formaldehyde will dissipate over time and in the meantime you should ventilate the interior well.
Before deciding what to do, perhaps testing would be in order so you know what the cause is. If there is mold, I would think that would indicate a major water leak(s) that would need to be addressed and there could be hidden damage.