Mold issues are a very important consideration and can be a deal breaker unless you are willing to just about redo the entire home in oder to erradicate the problem. We've worked with insurance companies for decades with claims like this and it can get pretty ugly not to mention costly.
Mold can and will creep upward from the bottom and eventually impact a huge part of the structure. The mold issue in this photo started underneath the home as a result of a drainage issue.
We were hired by the attorney representing this multi home class action lawsuit to perform destructive inspection on over 30 homes that had similar issues. By the time we were finished the framing (floor joists, rim joists, blocking, etc),sub floor insulation, particle board sub flooring, sill plate, wall paneling, insulation, wall framing and all the electrical wiring had been severly exposed to black mold which is very carcinogenic and all these homes ended up being a total loss costing the park owners 10's of millions of dollars in settlement and legal costs.
Be very careful and do get a thorough mold remediaton expert involved even if it costs you a few bucks.