Blackcloud6 wrote:What goes into the decision making when figuring out to siege or assault?
As you might suspect its complex. Remember that frontage plays an important role in combat so a large army cannot effectively be deployed to an assault. So a certain size of garrison will probably fight off any direct attack.
Time matters as does location. If it is garrisoned by a battalion or so and you are coming up to winter its probably worthwhile thinking about gambling on an assault.
Some places are hard to cut off so that makes siege hard. Montreal is one. Quebec less so if you have naval assets as you can send supply wagons back to the fleet, replenish and back to the land (fleets tend to carry more supply than they need).
It also depends a bit on the scenario. In the French-Indian wars both armies are small, so garrisons tend to be limited making it relatively easy for a large (relatively) army to take most locations by storm. In the American Revolution scenario both sides can generate substantial garrisons meaning that you end up with more long sieges or have to move a large army into a region in order to take control.