This is an offshoot of the Conquered! campaign seed. It provides you with a few ideas for building scenarios in a Conquered campaign.
Spying on the enemy is always good, gathering information which can be valuable to your allies is always desirable. The options for getting it out depend on the setting. The French Resistance can transmit it by radio and see RAF or USAF bombers pounding the targets. Shopkeepers in Port Royal can slip it to a fisherman who knows where a pirate sloop lies up. The advantage of getting information out to an external force is that it won’t incur retributions – that ammunition train could equally well have been pinpointed by aerial reconnaissance, or the sloop may just have been lucky enough to intercept the Spanish mail-brig. Sometimes there is nowhere to pass it out to, but gathered intelligence will always help the PCs make their own attacks more effective.
A really good option is to use it to manipulate the enemy forces – imagine the reaction of a town commandant when he receives a letter detailing the proof you have of him being involved in corruption, and threatening to take it to the Gestapo. Or if you can set up a series of tit-for-tat arrests, scandals, duels and disgraces amongst the occupiers they’ll do a lot of your fighting for you!
Hit-and-run raids on the occupying forces add a bit of excitement to the game through combat encoutners. Players will need to select their targets carefully: if they keep hitting groups of half a dozen soldiers on patrol they won’t make a significant difference to the enemy strength, but they will provoke a reaction in greater force. From a gaming point of view, it’s also more interesting to plan hits on significant targets, like the magazine of one of the ships blockading Port Royal harbour, rather than repeating the same objective.
Jailbreaks might become a regular thing: with PCs to extract from the execution cell, random hostages to break free of a holding pen, friends / contacts / relatives to save before interrogation breaks them and uncovers the PCs’ activities. After each escape, of course, the occupiers will increase their security and make it more of a challenge next time – or even make it a trap!