You would need to further clarify what you are trying to achieve.
What do you mean by “include all post locations using custom fields automatically” mean…? Are you saying you already have the coordinates of the posts as custom fields or do you mean something else…?
If there is no existing geo-relevant information associated with the posts, there is no magical way of adding it after the fact, not unless its formulated in some way with all posts from a certain category going to a certain location, but even then, that cannot be done out of the box and to be honest, would probably end-up messy, as its not very good when you have multiple posts or places in the exact same location…
If you could elaborate further as to what you really need, I will let you know if gPress is presently capable of doing or has it on its roadmap to accomplish further.
Several of these advanced directory-based features will be directed towards the BuddyPress integration elements, so its well worth taking a look at the BuddyPress gPress forums:
https://buddypress.org/community/groups/gpress/forum/
