You can do it either way. The risk threshold from my perspective is how much you charge in rent, with how large your deposit is, along with how often you inspect your properties.

Also, you have to be prepared to sue, file liens, and use sheriff evictions.

Everything is easier if you're local. If your investment is large enough, flying in to deal with your properties is a reasonable business expense (I wouldn't do it outside setting up a company and having general liability in addition to your normal house insurance).