You can double click on the leader's portrait to re-centre the screen, or single click on a non-lead character to make them leader and re-centre the screen (can also switch leaders using the F1-F4 function keys).
If you want to go to the market 3 screens away, for example, some people would find it easier to scroll the screen over and click than to scroll/click 3 times, or hold the mouse button down to direct the party to the market.
Eventually we should be able to move the screen focus somewhere from the map, which would make it much easier moving around areas that have already been cleared.
I don't know about limiting scroll distance, but there should eventually be an option added to disable scrolling with the mouse.
