There's a strong demographic of folks who are into publications like Dwell, Archdaily, Treehugger, etc. that are very interested in modular/prefab construction and in some cases that fact alone can lead to quite a bit of buzz especially around new development. 

I have a lot of learning to do, but my main interest is multi-family dwellings, commercial spaces in the future, possible vacation rentals and/or trailer parks. 

They’re telling him his garage is too large as an independent dwelling.

they considered it a dwelling unit and can qualify for opting out of VRLTA VA 225-55.01 if they expressively write it in the lease.

Would anyone have any advice or resources on getting started in a new city if my goal is to owner occupy a multi-unit dwelling (budget: ~175k)?

You will need a vacant dwelling or builders risk policy.If you have any more questions or want help looking over offers from HMLs post them here and we can go through them.You will want to ask the HML some questions too.

All dwellings with 3 units and up require a green card.

Jerry,Depending on what the project is there are several options:- Renovation Builders Risk policy for the building & separate Liability- Vacant Dwelling policy endorsed to include the renovation- Homeowners or Dwelling Fire policy that will allow the renovationWhich option is best depends on the work to be done, duration, whether or not the building will be occupied, etc. 

Would love some feedback on a property I just put an offer on:$130000 price tagPutting 25% downTaxes are $1676Has an adjacent dwelling on it so the total gross rent income is $1450Property Manager is charging me 10%.

If you're looking for a house hack I would wait patiently for the right 2-4 unit that works well for you and your own individual needs or I would buy an older SFH with an accessory dwelling unit (or the opportunity to add your own or convert an unused structure on the property).