I have to agree with previous posts on The Holmes Bde and 24th Mo as we are "brother" units, and if you want progressive, either is a good choice. The Holmes guys fell in with us at Twin Rivers last year, we fell in with them at 150th Pea Ridge Living History, and some of them are planning to fall in with us at Vickburg/Raymond. I'm biased obviously, but either is going to give a good impression and both work hard on that aspect of the hobby. If you want more mainstream, then there is also the 17th Missouri Inf in Mo and the 77th PA in Eastern OK who are both good people and good units and haven't been mentioned here.
Cannoneer, Fort Sill Historic Gun Detachment
24th MO Vol Inf
Lawton/Fort Sill, OK