I brew 10 gallon batches w 3 vessel keg system, outdoors, even in winter. When raining I have one of those pop up vendor roof tents, a little snow is OK if dry, but admit I don't brew below 20F anymore. It takes me 5 hours from set up to break down on a good day, maybe 6 if I sanitize some kegs and a conical, clean a bit more. It is kind of exhusting I have to admit, and look forward to day when I move rig indoors to more permanent set up. The dueling 220V outlets and a controller have sped things up about an hour. These days, I remember to go in and get something to eat, sit down and maybe write snarky comments on HBT to give legs a rest. For me, it takes almost exactly the same time to make a 10 gallon batch as it did for a 5 gallon batch before I upsized rigs.
Here are a couple of time saving tips though;
Start boil during during sparge as soon as electric element is covered. When I was running propane, I 'd start w 2 or 3 gallons in so as not to scorch wort. This is biggest time saver.
Heat sanitation water (for plate chiller, any empty kegs, and sometimes fermetor) in HLT during boil. Clean during boil, put stuff away as you go when finished with it.
When boil is off, I drop wort temp in BK w immersion chiller down to 150-160F for hop step. This temp drop happens very quickly and you can have cooling water on low flow. It generally takes about 5 min and uses less than 5 gallons cooling water, take out immersion coil and whirlpool to get trub centered. Hop step is done in cleaned out mash tun, if you transfer right you can leave all the hot break and some of cold break in BK. Pump to fermentor by way of plate cooler. If needed, cool wort to pitch temp. Glycol chiller speeds this up. I don't mess w starters, either direct pitch dry, or there was already yeast cake in fermentor. Not waiting for cooling is next biggest time saver.
One last thing is to think though steps for efficiency. If going to get something from inside for instance, see if there is there something you are done with you can bring in on the way. I kind of try to think like I did when working in a restaurant line kitchen.
But yeah,,, it is kind of tiring, but like to I figure it as I got a decent work out.