Austin, Texas in my mind is a 10.
Almost anywhere you travel you can find major roads with ample bike lanes or side streets with little traffic. Many roads have well marked 'share' lanes and the population is on the most part cyclist friendly.
Also, several communal bike repair shops that will help you wrench out your problems and share components. And the LBS range from national chains to mom and pop and hipster staffed shops that are mostly very helpful.
Austin is a true paradise...course, I was born and raised here and have never lived anywhere else for 65 years so I may be just a tiny bias....HOOK'EM