Answer
How far apart should meeting points be from each person?
Quick answer
Each person's drive should be within 5 minutes of every other person's. A small imbalance is fine; a 30-minute gap means somebody will feel they're doing all the driving.
5 minutes is the 'won't-be-mentioned' threshold. 10 minutes is noticeable. 20+ minutes and someone will reschedule.
If the geometry can't get under 5 minutes (one person in a remote suburb, another downtown), rotate who hosts the next meet-up so it's fair over the long run.
Free midpoint tool
Find your halfway point.