I'm thinking about buying the property to either buy and flip or just renovate and rent out.

I agree on kitchen and bath usually being the noticeable and having a good ROI, although they can sometimes be pricier renovations.

There may be some structural problem with the roof as the neighbor said he can see that the knee wall seems to be pushing up on the roof.I have no idea how to quickly get the numbers on all these renovations.  

The challenge is that it doesn't need any work (seriously, it's spotless), so going the hard money route, renovating, then refinancing with a conventional loan doesn't seem like an option.  

I would definitely talk to your bank that is giving you the line of credit and ask them to convert this home to permanent financing now that it is renovated.  

My advice would be: if you cannot inspect the home prior to purchase then adjust your offer to compensate for a full interior renovation - flooring, plumbing, paint, many fixtures, etc. 

For full out renovations I use name brand valve sets with replacable valve stems, enameled cast iron tubs from HD, and white subway tile with detail accents for a classic looking reasonably priced tile job.

Hey that looks just like the current state of my renovation! 

One area you need to analyze is the cost of the renovations you are going to be doing.

We house hacked our first rental and used that money to fund our renovation on our VA loan.