Having played maybe… 15 weekend theater LARPs… I can talk a little bit about methods I’ve seen.
A lot of them divide the LARP into time periods (usually five, Friday evening, Saturday morning afternoon and evening, and Sunday morning) and have mechanics reflect that. (For example, you might have an ability that can only be used once per time period.) It encourages pacing on the part of the players – they might hold off on trying to complete a plot until they can use their abilities again. It also enables GMs to introduce small (or large) but expected changes. For example, a number of them distribute money and other resources at the start of each new time period.
Scheduled events – things like “we’re holding a poetry contest from 2:30 to 3:30” or other in-game performances, formal debates, scheduled duels. Sometimes they’re less public and only known to a few PCs (“a shipment of supplies for the enemy is coming in at this hour, at this ambushable-location.”)
General, non-plot activity options – some LARPs provide space where people can try culture activities. For example, providing the materials and rules for historical board games (or sports, if you have the space) or materials and instructions for art projects. For example, Shogun provided spaces where players could enjoy a game of Go or try some origami.
I think the best way to make this sort of thing successful and appealing to players is to make sure there’s a set-aside space that is comfortable to just sit in (some LARPs have made this stuff available but not a space and it’s up to players to find somewhere that isn’t too awkward to be in.) while also not being too cut off from the main game. Players may not consider it a viable option if they’re likely to miss out on important stuff because they got absorbed into a game or project in a side room and are too far from the main space to be reliably kept in the loop.
mini adventure/quests/activities – a few LARPs had little… events players could pick up and play out whenever they liked. For example, Siege of Troy had a room set up with tape and piles of envelopes on the floor, where players could follow the tape paths and have mini-adventures (sort of like Choose Your Own Adventures) at each of the locations. Later runs introduced some limits to how often they could do it (like… twice per time period) because some players were just in there all the time. Introducing some costs and potential losses is another way to keep players from just absorbing all of the loot and rewards for success. Sometimes some of the adventures are only available at certain times, like… after the stars right on the Equinox or whatever.
Tales of Pendragon had time periods where players just picked one short Tale after another – not unlike mini-LARPs where they temporarily take on the roles of the characters in the story, and they could take as long or as short as they liked on each. There were also mini-games to represent players going off on hunts and such.
War games – some LARPs have wargames running throughout, with set times for turns, players looking over a map and sending orders for movement of troops and supplies, and GMs returning with the result, or players play out the battle scenes, either through a board game mechanic, or allowing players to temporarily take the role of troops or resources on the field. (One LARP had a single battle scene where players still played themselves, but basically as a piece on a giant board game.)
Timed releases of information – a lot of shorter theater LARPs basically front load the LARP – all of the information is there somewhere at the start, and players have to figure out how to access it, by getting it from one another (or the environment.) Weekend long LARPs often have new information seeded into the LARP over time – things like a newspaper that gets printed once a day, telegrams coming in, or new stars appearing in the sky enabling people to interpret them and act accordingly.
I have seen some amount of enforced waiting, and generally, people aren’t a big fan if they can’t do anything else in the meantime. If you’re a chemist creating new chemical compounds, telling players they have to essentially sit in their lab space and do nothing (or just mime mixing chemicals) for ten minutes is basically just frustrating the player – if you want to introduce the ten minutes as a balancing mechanism, let them start the process, and then do what they like and return after ten minutes to obtain the results. It won’t slow the pace of the overall LARP as much, but making players just sit and wait can really suck for the player.
I’m not sure about explicit pacing directions… is that like, “we recommend you don’t confront your enemy and demand a duel until Sunday morning”? Something like that has come up in a number of weekend theater LARPs, but it’s usually something like a moratorium on killing that ends Sunday morning. Duels always end in injury until then, but on Sunday morning, they can end in death. Or bad guys have escape abilities that always let them jump out the nearest window that stop working as of Sunday morning.