In many markets there are contractors who specialize in MH work. Initially, I had the good luck to find one with liability insurance (with my own insurer). If you use an uninsured/unlicensed contractor and they do work that later proves flawed (I’m thinking primarily electrical and gas), and heaven forbid, causes a fire in which someone gets hurt, you COULD be liable.
Word on the street will help you determine who is a reliable worker and who is not. PMs are the best source for contractors, unless it’s their brother-in-law who owes them money.
In a different market now, I use handymen, the best of which is insured. For any furnace/electrical/plumbing work I pay for a professional.
Just a quick aside: free MHs are often anything but free. My first Lonnie deal was “free” but needed everything. The drug dealer who had left the place took plumbing, light fixtures, the kitchen cabinets and sink and the toilet with him. He even sold the furnace and hot water heater. I believe in paying for education, so I was prepared to learn on this MH, even to lose money. It was a great education and I will get all my money back by the time it’s paid off (still has the original buyer from 2003 in it). I even sold it without a kitchen, but I did put in all new carpet, a new entryway and all the mechanicals.
If you plan to make money on your first few Lonnie deals, run the numbers over and over again. And buy cheap. And maybe avoid the “free” ones.