Niagara 1814 is a scenario book for Blackpowder. As with any book of scenarios, however, they can be adapted to whatever rules set you play
Gnome Stew has an interesting form to help you plan gaming adventures. It gives the game master a place to record locales, story goals, adversaries and treasures. It is intended for role playing, but I think it also would be useful for those story-driven miniatures skirmish games.
The Wasatch Front Historical Gaming Society offers a new colonial campaign: The Return Of The False Prophet of the San Juans.
From the description:
This is a fictional Sudan campaign in tribute to the Washington Wargamers and Lynn Bodin who had a fascinating campaign during The Courier’s Sudan theme. All of the players are on the Anglo-Egyptian side and the campaign is card driven, which produces a lot of chaos and uncertainty in planning. The campaign features the initial rebellion, cards for the Hicks expedition, the arrival of Gordon, Graham’s forces, and finally Kitchener and the Re-Conquest. The PDF contains the rules, cards, counters, and a planning map, plus you can dowload the full sized map below.
Over the Hills and Far Away is a regimental campaign game from the fertile gaming mind of Jim Wallman.
Quick Play Low Intensity is a set of free wargames rules for playing campaigns set in Vietnam or similar conflicts.