But I really don't know, I'm not an agent or a lawyer, so please seek professional guidance, for sure!

You need a skillset that you can manage tenant's expectations and enforce the lease with a professional but firm manner.

Kind of like a cash for keyshttps://martinezlawcenter.com/new-rental-laws-in-california-...Most of the long time investors I know haven't had problems but if you get a "professional tenant" in look out and call your RE attorney.  

I was hoping to get some professional opinions and expertise. 

I am sure there are other good choices out there, but strongly recommend them.Stessa is lacking tenant communications and maintenance tracking, but overall stands up pretty well as free, or nearly free.Buildium is pricey and has a learning curve, but if you are going to exceed 20 units, definitely look to migrating to a real professional package like buildium

Readers should seek professional advice.

I will have a contractor do most of the work from now on Did you work with any real estate professionals (agents, lenders, etc.) that you'd recommend to others?

Readers should seek professional advice.

Said tenant failed to hook up the drain line properly both times.

Ferd Niemann is a popular lawyer for MHP transactionsMake sure to take your due diligence very seriously and get professional help if you don't have experience here.