My other favorite period of gaming happens to be the Napoleonic era. The Peninsula campaign can make for some great games with epic battles. On July 28th, such a battle took place where Arthur Wellesley began the campaign to retake Spain. Wellesley, as he did famously at Waterloo, forced an engagement, but played a defensive role in the battle.

France
Joseph Bonaparte (41 Battalions, 56 Squadrons, 13 Artillery Batteries)
46,138 Soldiers
80 guns

Britain
Arthur Wellesley
26,641 Soldiers (30 Battalions, 24 Cav Squadrons, 4 Artillery Batteries)
30 Guns
Their Spanish Allies
34,993 Soldiers (34 Battalions, 24 Cav Squadrons, 4 Artillery Batteries)
30 Guns

As usual for the Wargame simulation, I would recommend using this order of battle. https://en.wikipedia.org/wiki/Battle_of_Talavera_order_of_battle

Wargame
2- 20 Players (If more than 3 use an umpire). Each player could easily control a division, corps, or faction.
Rules, General D’Armee, or any other large-format Napoleonic Wargame
Table 16×8 for 15mm, smaller for 6mm
The terrain is arid, with some bluffs; the river did not really apply much.
Use the order of battle to determine troop quality. It could help balance the game by making the Spanish closer to the militia.

Scenario
The French should be the aggressor and attempt to move the British and Spanish forces from a defensible position. The French should have a higher quality of troops than the Spanish.