You are spot on about preparing for the weather on those high rides. Whatever clothes you bring, you will think it's too much on the way up and you will know it's too little on the way down.
You have to pick the right day, and they can be fine, but you still have to bring a lot of clothes for descending. A packable rain(ish) jacket, long finger gloves and an ear band are *minimum* even on a "perfect" day. Both rides have significant time above tree line, where wind can be a very big factor (15-25 mph is normal, 50mph is not uncommon) and have afternoon thunderstorms regularly. That said, I've ridden both multiple times, and only had to hitchhike once off Trail Ridge, in a sideways hail storm. Luckily, friendly people in pickup trucks are the norm here.
Here are some weather links:
Top of Trail Ridge
http://forecast.weather.gov/MapClick...&FcstType=text
Top of Mt Evans
http://forecast.weather.gov/MapClick...64200&site=den
There's a race up Mt. Evans, (Bob Cook) racing at 12-14,000 feet is kind of ridiculous, but what the heck.
Here's a ride you should do when you get to boulder, it's a classic, moderate (?) climbing ride:
http://goo.gl/maps/pHL4m
all the "letters" have services, don't miss the home made cookies at the general store in Ward.