Hello @Sinil Kim,
I'm a newish investor (I have 5 doors). I live in South Florida and was looking for small MF's and was having trouble finding cash-flowing properties (looked at 100 properties). I ended up purchasing a mixed-use triplex in upstate NY near Binghamton. I've never been there before. I didn't visit the property. I read @David Greene's book about how to invest out of state and followed his action steps to purchase a property out of state. It took me 3 weeks between reading @Brandon Turner book on how to purchase rental properties and David Green's book before I started making offer. It takes effort, but it's not complicated. "Out of State" really refers to any area that you're not familiar with and can't self manage. The tools you learn are tangible and helped me with my purchase. You will need to get interview and find a good realtor who knows the area well, general contractor, maintenance person, and property manager. Generally speaking rock stars know rock stars....so if you can interview and find one of those you can get to others.
In terms of where to invest, maybe network with someone you know who is in an area that you can afford and has the cap rates or CCROI you're looking for. Start with social media circle, if one of your friends doesn't invest in real estate, someone in their circle probably does.
In terms of if you should visit the property, I don't think it's necessary. Go to google Earth, you can visit the neighborhood that way. Personally there is nothing I can do from a maintenance/ fixing the place. When looking at a property I would ask the realtor to take more detailed pictures of any properties that they go visit. Then if there are any issues that need repair you would have your maintenance man or GC take extremely detailed before and after pictures.
Hope this helps :)