Ok, you have a cool bike and people have toured (me included) on less. The issue will be the bikes you are touring with, are longer winded, In other words they will cruise at a higher speed and not have to work as hard. Depending on the weight they carry, your bike will be working harder to keep up. I'd check into your gearing (sprockets) to lower your engine speed at higher speeds. I'd also practice packing, get gear that is efficient and light weight. Talk to campers and hikers, they'll give you a lot of info. Talk to your buddies and see if you can all figure a way to spread the weight out among the bikes. An XS 1100 can carry hundreds of pounds and not even breath hard.
Make sure you know each others health issues. One of you may need to eat on a schedule or relieve themselves regularly more often than the rest of you. Know where you're going and what the time frame to make your destination. Get together and pull together a good assortment of tools and things like duct tape, zip ties, electrical connectors, fuses, patches etc. and being on older bikes, watch oil consumption....
South west Utah is awesome, Bryce, Zion, the North rim of the Grand Canyon (Az.). Now, you need to remember, heading to California, you'll be crossing one of the biggest deserts on earth, you need to keep hydrated and covered. It's easier to wash off sweat than recover from serious sun burns. Not sure why you're coming to L.A. maybe family? But If possible I'd skip it. The Sierra's and the central coast up is where it's at. The 1 doesn't even get interesting till above Morro Bay, but there are thousands of great mountain roads. From Cambria to Monterey is simply amazing, from sea level to hundreds of feet above and back to sea level more time than you can count, it's amazing. Maybe on the way back ride through Yosemite and out through Lee Vining and make a stop at Bodie, then down through Mammoth. These are all just Ideas. You guys are going to have a blast, just know your limits and take extra good care of yourselves...
