In a previous question we determined that to survive on an alien planet, we'd be heavily reliant on stuff we brought with us. Whatever plants we could convince to grow that we happened to have on hand, plus "processed" foods using yeasts.
- We have access to Bread Yeast, since the original ship had a half-decent kitchen.
- We have access to Beer Yeast, since someone was almost certainly brewing something on board, legal or not.
- We have access to a limited number of Earth foods that were preserved and able to be planted. Not an extensive list, but things like tomatoes, potatoes, and the like could likely be grown. This article sheds some light on what might or might not grow.
- We have access to wagons and carts and some form of beast of burden for transporting things. More along the capabilities of an ox than a horse - Not something that would be used for personal transport, but good for moving loads.
So, we have ourselves fed, but we can't go out into the wild and pick something, or hunt something, and eat it. While they might not be toxic they're not going to be nutritious or sustaining.
It's been a century or two since we've made landfall, and we've regressed back to a "Middle Ages," before firearm, technology level. We still have writing, although literacy has dropped. We never really dropped much below middle ages, as we were able to make do with what we had to get this far. We've grown, and split into factions, and then nations, and as nations do, they war.
How do we keep ourselves supplied? One of the primary methods of resupply in such a time period was to forage and hunt, both of which are pretty much out. Sure, you can steal stuff from the enemy, but that will only get you so far - Especially since they know this and can adopt a scorched earth policy.
What sort of logistical wrangling would be needed to keep an army in the field under such conditions, and what sort of "Maximum Range" would they have, if any? Are there rations that would be sufficiently nutritious that would also keep for long enough? New addition: Could a network of ships and waterways be sufficient, especially if the civilization were built around such areas? There is historic precidence, especially for farming - A significant factor in this world.
As a note: I'm not necessarily looking for how warfare would change (That would be the scope of another question), more for how the logistics of keeping an army at a distance would change