Running (ie characters moving), and how to handle it

Sorry if this is a basic question. Ive been a subscriber for years as i like the idea but have only 91 hrs, and mainly as a player experience on the system. I was thinking of starting to use the system, and i was wanting to know the best way to handle what our poor GM got stuck with last week. A party ended up having a running battle in the woods, chasing down the attackers. With a fast monk dashing, and a slow halfling moving with caution, very quickly we ran off our A1 hex map and had to start adding extenders as the distance between different character members got bigger and bigger. If i make a map in Roll20, and i able to resize it to a bigger map if what was planned on being a close encounter starts being a chase combat and also a long ranged missle combat?
Andrew R.
Sheet Author
If I ever had that problem, I would Split The Party and move the Monk onto another page & map.
Personally I would switch the map to bigger scale - as in 1 square/hex is bigger - and determine what happens inside it in a "Theater of Mind" style. That requires far less work, can be more dynamic and more "Role Play-ish", since you don't get bogged down calculating everyone's distances from each other constantly.
I've done a chase in an urban setting by abstracting the movement, allowing characters to catch up or fall behind, and just used The map grids to show relative positions. If everyone is moving, you just need to track the difference in the movements. If you do expand the map as you go, you need to have the chase going to the right or down, as added squares are added to the right side or bottom of the map.
Thanks for the tips guys :)