If you feel the numbers you've reached are more of a best case scenario as opposed to a worst case, it may be better to simply walk away.

It has its own exterior door and another entrance into the master through one of the other Bedrooms. 

If you can pull money out of the property I would do that as opposed to some type of a conventional loan.

Which is obviously easier to secure with a quadplex as opposed to a duplex.The concern that I still have, is that I'm not sure a lender would approve me for a loan that large.

have them take photos of their stuff, keep all of their documents stored in a ziplock bag and kept in a secure place, bring in or tie down exterior stuff, get rid of flammables, if you have problem areas that collect water, then def hit those areas with tarp and sandbags.

Not knowing specifics or geographic location or power needs for this home and using basic code requirements a total rewire for a 2700 sf home with new hardware and trim excluding a new service would run somewhere in the neighborhood of $25,000, this does not include the repair to exterior surfaces that would be required to “chase” wires across beams and studs.

Your couple of posts here indicate maybe this is beong sold fsbo as opposed to being sold by an agent.

As opposed to single families and such?

The only maintenance issues you can do on your own (exterior) is Painting, Planting, and Pavement so generally speaking everything else needs to be approved.

The house has a finished roof, exterior windows and all of the weather wrap, but no siding and no interior pictures (assuming it would be at the most, dry-walled inside).