The choice of TH's to me is about the same - I like getting into the alpine and away from other "trail hikers" as quickly as possible. The "Middle St. Vrain" TH (from CD) is a little longer, more popular and much more scenic - the Beaver Creek TH is shorter but gets you into the alpine faster - the first 4 miles is a 4WD trail which truly $uck$ for hikers - it's best to get a sunrise start to avoid the motor vehicles. I mostly hike off-trail - I'll use a main trail to get me into a general area then go my own way, scrambling, screefields, snowfields & tiptoeing through the tundra.
If you come in from MSV - it's about six miles to Red Deer Lake - nice camping spots on the northern side, up on the crown overlooking the lake. The melting snowfield at that end can be quite loud this time of year - take earplugs.
No sooner do I mention the limited rain in the Rockies this time of year - the "current" forecasts are now showing rain in the coming week or so. Front range Colorado can go into it's summer monsoonal pattern - dry mornings with afternoon showers, then drys back up - as it gets said, if you don't like the weather in Colorado - just wait 5 minutes. The rains is not a problem but the lightning can **** you - or just scare the heck out of you! Be safe.