Looking for some advice on a deal.

[Jose Botello]

A partner and i currently have the opportunity of purchasing a 4 bed 2.5 bath house with existing tenants. the seller is a close family friend that has had the house for about 14 years, he has had the same tenants in the house the whole time. He says they have only ever called him maybe a handful of times in those 14 years. it is an elderly couple in their 70's they always pay rent on time and don't mind that the house is outdated. 

the house was purchased at $31K when the owner bought it. he is wanting to sell for $39K. house has 7yr old roof, 2 yr old furnace, PEX upgrade through whole house and painted the outside about 5 years ago. He also mentioned the house was appraised a few years back for $80K. 

it is currently is rented for $550. at a purchase price of $39K i feel like its a decent deal considering the market. 

am i missing something i should be on the look out for? 

how do i go about for insuring the place if we do buy? 

any other advice is appreciated as this would be our 1st deal! 

thanks in advance!