Help! Take the deal or no deal?

[Wee Pone Yang-Chang]

I just put in my first offer for a duplex and amazingly it got accepted on my first try! Once fully rented, my potential CoC return is about 20% or $520 cash return after all expenses paid. Location is great, down the block from the University. Accepted offer is $170,000. But after inspection report came out, I think I'm having cold feet. The home is built in 1920. Please let me know your thoughts: gutter repairs, front and back deck repairs/replacement, several holes/roof damage to unused garage, eventual replacement to galvanized plumbing, eventual all window replacements due to lead.....Biggest concern: Both furnaces are OLD and are nearing end of life expectancy. I can't stop thinking that I'm getting myself into a money pit. I would like to keep this as a rental for at least 5 years or more, some updates but don't want to totally renovate it. The seller is refusing to fix anything but is offering $5,000 credit at closing. Should I do it? Total renovation is not in budget right now.