The whole foundation system is modular and installs in 1 day.We do meet state and city requirements and have approvals in Sonoma, Marin, and a few other counties as well as working to get approval for a primary dwelling in Mill Valley and Fairfax.The structure can be disassembled and moved easily because of how it's designed but it's far too big to be considered "mobile". 

Greg,From an insurance perspective, we have over 40 Markets for Homeowners & Dwelling Fire Insurance and only one will consider Knob & Tube (and only if it is a limited percentage of the wiring) or Aluminum wiring.

I see myself in the middle and can say that I'd probably be happy with my first purchase being either a house-hacking situation that I would live in and rent other parts of the dwelling out, OR purchasing something in an area I'd eventually relocate to with a tenant already in place, paying the mortgage until they move out and I move in.

I fully intended to rent it out by the room, but while reading some HOA documentation I discovered it very clearly states:"Leasing: Any dwelling that is leasedshall be leased only in its entirety; separaterooms, floors, or other areas within a dwellingmay not b~ separately leased;"Short term rentals are not allowed, either. 

We have a basement that was used as a dwelling unit, but not permitted by the previous owner.

You will need to find out if your umbrella policy will be allowed to go overtop of your rental dwelling. 

Our specialty is 2-4 units dwellings :)I might throw in another $50-$150 if I know something big is breaking soon.

And what if the dwelling wasn't rented out yet, does that pose a financing challenge as well? 

Arlington county has relaxed its standards for accessory dwelling units (https://housing.arlingtonva.us/plans-reports/accessory-dwelling-ordinance-update/).

Rent Roll with specific dwelling number, name of resident, move-in date, monthly rent, amount of deposit held, current balance, additional charges, number of occupants, and a brief history of the resident (good resident / bad resident, special circumstances, etc.)