Looking for someone with some Old West knowledge

Hello everyone, in light of some recent information I have learned from people here and through my own research, I have decided to move the setting of my novel. The problem is that it is historical fiction and so I need a place that fits my plot.

Right now my MC is leaving from a fort to go on what is essentially a filibustering mission and later deserts the army, heading to a nearby town to hide low for a while. I was originally using Kansas as a setting, having them set out from Fort Harker and escape to Ellsworth, which was close enough to reach on foot.

The problem is that I couldn't find accurate depictions of the surround scenery, and the plot of my story depends partially on a traveling and fighting in a forest. Upon further research it seems like an old growth forest would be perfect, but unfortunately it seems that the area around Fort Harker doesn't fit the bill. Does anyone happen to know of a military fort that was active around 1870-1880 and that was reasonably close to both an old growth type forest and a neighboring town? The forest can be a days ride or so from the fort, but I need the town to be reachable on foot within roughly a day. Thanks very much to anyone who can shed some light on this, I know we have some really awesome Western fans here so I am hoping someone has come across a setting that could work.

I'm trying to look through all the forts, but the trouble is finding information on nearby towns or forests, especially in regards to how it would have looked in the late 1800's. Something I am looking at is Minnesota - I know there are old growth forests there, and Fort Ridgely has some interesting history and established towns nearby, but I just cant find any information on whether or not there were any forests nearby. It doesn't have to be right next to the fort or anything, but reasonably close, and the forest can't just be woods, but something substantial where a small battle could take place and people could hide.

Argh this kind of research is so frustrating.

Yeah, I am looking for actual large forests nearby. I am trying to find more information on forts in the states you mentioned, but there isn't much out there. What little I can find doesn't really describe the area around the fort or what towns were nearby, and a lot of the towns that were near forts weren't founded until much later.

I'm thinking I may have finally found it with Fort Buford in North Dakota, which was relatively close to Yellowstone if my information was correct, and had a trading post nearby as well. It isn't a town per se, but it should work, and the forest part is perfect. Thanks again for your help so far, and if anyone else has any places in mind or some more specific info, I am all ears for that too

Whoops, I meant to say Yellowstone Rivers, not the national park.

By "old growth" I guess I mean a forest that isn't just a small little patch of trees, but something large enough and dense enough to facilitate ambushes and a short journey through the forest. And yeah, I know most of the places were logged already, so I am hoping there is something that fits what I am looking for. I want to be as historically accurate as possible; I don't mind embellishing the scenery a bit, since it is hard to judge exactly what was where in terms of forests and such nowadays, but I don't want to invent a forest in an area that was historically a prairie or anything.

Also, thanks for the tip about the maps, I will have to search harder and see if I can find some. So far all I have come across are old photos or top down photos of the fort itself, but nothing including the surrounding area.