The setting is an earthlike world, in a temperate zone. The world is fairly low-tech; there was an apocalyptic war a few thousand years ago and the world hasn't recovered from it yet in terms of population and technology. There are no mechanical or magical methods of travel. They're limited to walking, riding horses, carts, and wagons.
Because of reasons, I need to have my circus go cross-country for a few days to get back to a road. At this point, they're breaking trail through a thickly-forested area. Wagons are not ideal due to the lack-of-road conditions, but they do have some for the most essential and unwieldy things. However, anything that can walk and not try to kill people isn't riding in a wagon. They left some wagons behind in a town they're going to get back to soon, but they left that town to do a show, so everything that they need to live and have a show is with them. Time is a bit of the essence, as their break from the road has cost them enough time that it's now moving firmly into temperate mid-fall where they are, and the occasional heavy rain slows them down (I assume).
In this world, the circus's function is partly entertainment, partly informational, and partly clandestine. They generally stay 1-3 days in a place before they move on, and they move rather slowly, but they're supported as much by government and criminal pay as by ticket sales so the money isn't an issue - being able to gather information and get it to the right places at the right times is.
I've done research on the history of the circus, and I know that the first big top was developed in 1825 and the Virginia Pavilion Circus was, according to The Rise of the American Circus 1716-1899, the first circus to do a one-day stand and move on, so it's practical to do a show without the benefit of a railroad or a semi truck. VPC seems to have been Brown & Bailey under another name, and if that's correct, they had a very small crew - 13 or 14 people for that first one-day stand. The Washington Circus of 1826 (Quick and Meads) had ~12 people, 7 horses, and a pony, so clearly not everyone was mounted as they went from point A to point B. I've also seen a route book for Sells Bros. Great European Circus of 1878, and while they have a lot of doubled and tripled names, there has to be at least 150 people on that list, to say nothing of the equipment and animals. However, that is a railroad show, so it's too big for my purposes.
And now, finally, onto the questions!
1) How big a circus is reasonable under the circumstances? I am able to fudge, to some extent, what kind of equipment they have (for example, perhaps the big top doesn't have seating, or perhaps they improvise seating on site) and obviously this doesn't have to follow earth rules exactly, but for story reasons, I would like to have this be a circus of about 75-100 people, mostly performers who take care of their own animals and double as wagon drivers and support staff if possible, and I'm not sure that's not insanely too big. I can't figure out the balance of people, animals, and wagons to load of food and equipment, multiplied by days of rain or whatever that would tell me how large a group I could comfortably move under these circumstances. I would also like to have one big top (80 feet across or so) and maybe as many as five significantly smaller tents (say, 10 feet).
2) Since this troupe, unlike railroad and truck circuses, and even early wagon circuses, can't count on being under shelter at night, I assume they carry sleeping tents with them at this time of year and under these weather conditions. This is a major problem, as I have never been camping under a tent in my life, and have no idea what might be a practical option here. Giant pavilions that sleep twenty? Pup tents with the person's feet sticking out the end? Four-person jobs? The troupe gets stuck for a day due to heavy rain; a modicum of comfort where someone can come into a tent and have a conversation would be nice, but I'm not sure what would be actually practical in terms of load balance.
3) I'm quite sure that there's an equation out there that takes into account the number of people and the number of calories they're expending, the distance they're traveling and under what conditions, and the weight and volume of food and tells me how much food everybody needs to get to the next town with just a little bit of reserved food (which is used up in the stop for rain so they get there with no food and are hungry). I do not know what it is, and my brother's experiences of hiking in Scouts has been useless as far as figuring that out goes. Since several key scenes take place over meals, it would be nice to know how many wagons they're using for food, assuming a diet that fits what I think of as Russian - so lots of potatoes and root vegetables, proteins of some kind, and some carbs. The land that my characters are currently in is derived from Central Siberia, though less cold, and it's not really rice country, so that would affect what kind of food they have with them, and how it's prepared. It doesn't need to be exact, but I'd like to get a sense of how much of their load space is dedicated to food, for both themselves and the animals (primarily horses and felines at this point, and they're going through coniferous forest so no grazing), because if I need to have twenty wagons for a troupe of 50, I am going to wind up rethinking this section of the book significantly.