My wife has a Jamis commuter bike supplied by her employer as a parking and state clean air law incentive. I've always had a thrift store/yard sale beater bike around, but never really got into steady use. I tuned up a hybrid bike with a better seat and lights, but it was a fat tire rig and hard to keep up with my wife on 32c randonneur tires and paved rail trails. Then I lucked on a Trek PDX aluminum commuter bike in a thrift store for $70. That created a biking explosion much like getting into UL hiking.
I've been tweaking the bike for local trips and rail trail cruising for the last couple months and we've been having a ball with regular rides. I'm to a point of physical condition and equipment that some short multi-day trips look promising. My plan is to use my usual UL hiking equipment for shelter and cooking. The only specialized clothing I've added is a rain jacket and padded shorts, and of course a helmet. Camp clothing comes straight from the hiking gear locker. I have some used panniers that will hold my UL gear easily. Add water and pedal :)
Max Dilthey has been a great resource for information and inspiration. I enjoy his blog and he has given lots of good advice on equipment and maintenance. http://maxthecyclist.wordpress.com/
This is the bike as I found it. It's all stock except for the SKS fenders.
And this is what it looks like today:
I have arthritis in my neck and tried a couple schemes for getting the handlebars raised a bit so didn't have to raise my head as far. I found the Origin8 basket/handlebar combination. That takes care of my wishes for some sort of front rack and it is great for urban errands. One reviewer hauled a 29 pound watermelon with one, so it should handle any UL gear I want to haul. Odd that a 12 pack fits so nicely :)
The rear rack is a Toba Roger Randonneur. My bike has disk brakes and that really complicates the rear drivetrain. Items like fender stays and rack supports can be a convoluted mess and this rack has an integrated fender and mounts on the axle skewer with one more attachment to the seat stay cross bar. Simple and elegant, much like UL hiking gear I think.
One great tip from Max was Schwalbe Marathon tires. My bike came with fast but skinny 28c tires. I changed them out to 32c Schwable tires and they work great. I would have gone to 35c tires, but 32's are recommended safe maximum for my rims. With the Marathons, I have 5mm of protection from flats and a great tread pattern. The high pressure rating is 95psi--- a smoother ride than the 120psi 28c tires.
Other than that I have added lights, a small wireless computer, a tiny bell and some water bottle cages and a kickstand. Biking can be as bad as hiking gear on small accessories and there is a pump, patch kit, spare tube, a small took kit, and panniers.
I'm looking forward to some hybrid trips, using bus and bike to get to a trailhead as well as more typical bike touring.