Tips on deciding wether to Airbnb or raise rent?

[Ken Francis]

Recently I have been tasked by my family to determine the best plan of action with the mother-in-law house behind their home. They recently bought this new home that they're living in and a long with it came a separate house which is currently rented out to a tenant who has been living there for years. 

The previous owner had made a deal with the tenant that they wouldn't raise rent on the condition that repairs would be forgone on this home. As such, this mother-in-law home is in need of some repairs (not sure to what extent). It is also being rented out for well below market rent. The plan is to kick out the tenant when their contract expires and to either increase the rent to market level or to use the home as a short term rental property. 

What advice can you give me to find and analyze current market rents in the area and how can I best compare that to using the property as an AirBnb. 

Side note- they would prefer AirBnb for the ability to have space for family when they visit. They understand that this would cut into their potential income but are willing to sacrifice this if their income would still be similar to what they would make if they decided to simply increase the rent and have a permanent tenant.