No size limit but I would try to limit yourself to 1 single bag. If a sleeping bag doesn't fit in it, try to strap it on securely. That said, the tents are cozy for 2. You need to be able fit your bag and yourself on one half of the tent. There is no other place to keep tha bags protected from the elements. I have used a big camping/hiking backpack for the 2 rides I've done and haven't had an issue. I loaned a similar pack to my brother last year and we all fit in the tent without issue.
Hey Sushiboy21 - unfortunately there are no showers at the end!!! I would pack some fresh clothes and deodorant in the car for the ride home....LOL. The best you might be able to do is stop off a gas station and wash up.
Re shower: as odd as this might sound buy a simple 4 gallon weed sprayer (the kind with the pump and the hose) fill it with water, leave it in your car while you ride to let the water warm up, and then when you are ready pump it up, place it on the roof of your car and voila hot shower.
/\ , i think there's a shower at "the sundowner",... wut? ... wait........:D j/k
re: packing - if you're tenting it , pack a glowstick to tie to your tent door / roof before you head out for dinner (makes finding it at 10pm WAY easier if too many beers and wine were/will be consumed)
A towel, it says, is about the most massively useful thing a cyclist can have. Partly it has great practical value. You can wrap it around you for warmth as you bound across the cold moons of Jaglan Beta; you can lie on it on the brilliant marble-sanded beaches of Santraginus V, inhaling the heady sea vapors; you can sleep under it beneath the stars which shine so redly on the desert world of Kakrafoon; use it to sail a miniraft down the slow heavy River Moth; wet it for use in hand-to-hand-combat; wrap it round your head to ward off noxious fumes or avoid the gaze of the Ravenous Bugblatter Beast of Traal (such a mind-bogglingly stupid animal, it assumes that if you can't see it, it can't see you); you can wave your towel in emergencies as a distress signal, and of course dry yourself off with it if it still seems to be clean enough.
More importantly, a towel has immense psychological value. For some reason, if a strag (strag: non-cyclist) discovers that a cyclist has his towel with him, he will automatically assume that he is also in possession of a toothbrush, face flannel, soap, tin of biscuits, flask, compass, map, ball of string, gnat spray, wet weather gear, space suit etc., etc. Furthermore, the strag will then happily lend the cyclist any of these or a dozen other items that the cyclist might accidentally have "lost". What the strag will think is that any man who can cycle the length and breadth of the galaxy, rough it, slum it, struggle against terrible odds, win through, and still knows where his towel is, is clearly a man to be reckoned with.
Given the uncertain weather forecasts I'm lining my pack bag with 2 large plastic garbage/leaf bags, compressing them and then tying them off. Even if it doesn't rain my pack will take more gear and if the pack is lying in dampness before I get it, things will stay dry.
highly suggest you put everything in garbage bags before you pack them in a hockey bag. When you get to camp the bags are already unloaded on the ground and only covered by a tarp. This way if it does rain and your bag is soaked, everything inside is nice and dry.