This is kind of late, but here goes:
1. I do every day -- from Brookland to Capitol Hill, ~ 4 miles
2. Since a major section has just completed being built, I now take the Metropolitan Branch Trail most of the way. The places from my house to the trail and from the trail to work are all without bike lanes. In general I prefer a street with a bike lane if I don't have to go more than a couple of blocks. But I also factor in road width (I will take a lane if it's really narrow but I prefer to avoid that), traffic volume, and road surface quality.
3. There are racks in front of the (large government) building as well as racks in the garage. I generally park outside (there are lots of police and it's pretty secure) unless the weather is nasty. One of my bikes is a folder which I've taken inside -- never tried this on one of my full-sized bikes but I suspect it's not allowed.