This quadplex looks promising and was wondering if I should go this route or in another direction. 

There are a few routes to try. 

Did you go this route and if so, how did you fare? 

Initially, I was focused on multifamily properties, but after doing more research and considering that I will be making Florida my primary residence, I believe that house hacking or short-term rentals (STR) may be the ideal route for me.i still will own my Southern California home; shift it to secondary.  

What would be my best route to take if we need additional finances?

We know what the cost is to pay for some work and determine if we do some ourselves, is the time vs money a route to go. 

If it were me, I would go the seller financing route first.

You can purchase them through a local dealer that has a good track record in the community.At this time our cleaners take care of the hot tub, but I will say if you have a certified hot tub company that can come weekly, I would definitely go that route!

Or you can go a DSCR route (sometimes with no seasoning) but the terms suck.

If meaningful appreciation is on the horizon, its a different story.If you were to go the financing route, blanket loan may be your best bet through small local bank or alternative lender.