Oh…I miss 10 hour sessions…12, would be a bit long…I’m going to ask questions and assume the answer…
What breaks do you have?
I assume a meal and a bio break every 2 or so? If not and people are just wandering as needed you have a less disciplined game…but with 12 hours that is fine.
But remember to give yourself a 10 to 15 minute break every 2 hours. And at least a 30 minute break at the 6 hour point.
These breaks can take on different aspects, one on one with a player away from others, in a dream or one on one exchange with the PC, catch up personally with the players, their lives and such. Or grab some headphones and zone out for a bit. Read up on your notes, draw a map…This is a mentally exhausting effort. Take some time to be less aware of everything and just on one or two things.
Start with light snacks, veggies and such, low/no caffeine. If you take a meal break, keep it light, but have some caffeine and sugar (this can be in the form of fruit or fruit juice). After the meal (middle point), start hitting the sugar and caffeine button as the craving hits…stay hydrated…eyesight is the first to go when not hydrated if you need an indicator.
In the last 2 hours, you can hit the light alcohol button as a sugar hit. But if you have to drive…that is a no go, just start tapping the breaks on the stimulants. Brownies and cookies are a possibility, beef jerky is another. And water!!!
Get them rolling or engaged right away…if you end the last session on a cliff hanger this is easy, but that requires great luck and skill. But even if it is the group helping a merchant catch his horses that got untied or a sudden break in a fuel line…get them in the game.
Give the players tasks…plan something, make a shopping list, figure out how they want to gather information…and you walk away, take a break, or eat something in earshot in case they have questions. But train them to be complete and recognize that questions should be limited while they figure out a course of action at these times. This give you a break from the mental heavy lifting. If they have better ideas than you had…adopt them…players feel clever and you seem smarter.
Let them have these moments of just them, encourage role playing…but to each their own.
When you fully come back to the table…answer their questions, give them results. And force them to implement their plan/shopping and move back on with the story. Don’t let them replan with you fully present.
Understand the objectives and let them run through them, but if you can orchestrate that they hit the boss fight at meal break…perfect. They come back and have an epic fight, let that conclude, and the last few hours is hitting the next adventure. Ending it just as the first combat would start.
Know your NPCs. They have plans, the PCs are a disruption. The NPCs are not speed bumps for the PCs…they have their own wants and desires.
Knowing what your main NPCs would do in almost any situation…allows you the freedom to let the PCs do whatever they want and you have the NPCs do what the NPCs want. When those desires have conflict…dice rolls happen.
Some times your players will walk all over your plans…make cool npcs that they enjoy humiliating…the players did it right!!! Don’t feel bad.
Other times your players screwed the pooch, and you need to tone it down??? Humiliate them, if the TPK is about to happen, strengthen the main bad with allies and take them all down in an overwhelming way…have the characters wake up in a pig sty nearly naked, with a brand on forehead, cheeks and butt cheeks. No gear. Except the internal stuff.
In ICRPG that is a reset. Let that NPC get stronger. Let them learn what the brands are after they start empowering themselves again. This NPC is now an arch enemy.
Brands can be anything, kill on sight, banishment, magical trackers, escaped slaves…summoning runes.
Or have a totally new starting adventure in your back pocket in case they all die. But those NPCs still exist and are still working their plan to rule the world.