I am still a newbie myself so I don't want comment with a lot of advice but I will tell you about my experience and maybe it will help. The owner I purchased from had 20 yrs of deferred maintenance and had not even been in a single unit in over 15 yrs. He didnt even have the keys to the units. He only raised rents one time in 20 yrs as well. It was however in a class A- neighborhood.
It is a 5 unit that the owner held financing for and I used my cash to pay for all renovations. This allowed the owner to hold the mortgage and gave me the opportunity to go in and renovate, triple rents, and stabilize the property over the next year with strong leases. My exit was to refinance and pull 100% of my cash out while still maintaining good cash flow. I am potentially able to do this because I have increased the value of the property significantly in the process. From my experience banks will lend anywhere from 75-80% of the value of the property.
The renovation part of the plan was a success. I have long term financing with the owner (15 yrs). However the refinancing part has been a little bit of a challenge. Very few banks are excited about it. They simply did not seem interested. I had to call over 25 banks and I finally found 3 that genuinely wanted to work with me. They were actually better terms than many of the mid size banks who were less interested or just found it bothersome. Focus on the smaller regional or community banks. You should find some. I am in the process right now of getting all the paperwork compiled so if everything goes well the plan will have taken a few months longer than expected but ultimately worked out. Keep in mind thought that almost all of the banks I spoke with have a 5 year balloon and typically will not amortize longer than 20 years. I did find one bank willing to verbally commit to a 7 -10 yr term depending on appraisal.
Hope this might have helped in some way.