My mom is selling her house

[Butch Cantz]

My mom is looking to move out of the city limits of Philadelphia and move closer to the suburbs near my family. 
I was hoping to purchase the home from her and use it as my first rental property.

She owns the property outright.  3BR/2BA Dow Home. Properties in the area go for $240k.  They rent for around $1750- $2000. 

She is looking to move into a 55+ community where modular homes go for around $185k with $600 in HOA fees.

I am trying to see the following 

1.  Is it possible to purchase her home with a realtor. 

2. what is the best way to go about it so we are all in a good spot.  I have an rental property and she doesn’t have to pay a dime where she is living. 

I was thinking of buying the home below value and and then with the rent, paying the mortgage and the alps paying her HOA fees for her

Thanks in advance!