While it's certainly not a solution to your need for a property manager, having family close by who can sometimes drive by or who have their own local vendor connections, will definitely be a help for an out of state investor.
One of my criteria is that I don't invest south of cities that I-10 passes through. That puts St Mary Parish out of my area. That's a matter of long term strategy to avoid ever increasing insurance rates due to hurricane risk factors. Generally speaking about rural areas, there is demand for housing and properties do hold value. You can expect a slower market. Slow to rent or sell. That still works for buying and holding, but don't expect to fill vacancies quickly with the small pool of tenants for rural areas.
That's enough generalization. :-) Here are some numbers to support my opinion. There are currently 67 ACTIVE listings in St Mary Parish. Over the last year, 55 have SOLD. That means there is currently a 14.6 month supply of houses on the market! The parish is between Houma and Lafayette, and this data is from the Lafayette MLS. There are probably a good number of properties that get listed on the Houma MLS so there's more information out there on the topic.
More than 6 months supply is a buyers' market. Equilibrium (or a balanced market) is 3-6 months supply. Less than 3 months supply is a Sellers' market. Think of each as replacing the word market with the word advantage. It is normal for a rural market to almost always be a buyers' market - that's why I call them slow markets. That's what makes them a bad place to try to flip houses and why it can still work for buy and hold investing. As long as you are realistic about your expectations, you can do well there in the long run.