For people out there who live IN the District, where do you do your non-commuting rides and what is your route out of the city? Most of what I have found here and elsewhere is on MUPs, which I find boring and crowded.

For reference, I live in U Street (on the AdMo side) and ride mornings/weekends.

Your best bet for staying in the city is to ride east of the Anacostia...long hills, low-ish traffic, some wide streets. I wouldn't ride out there during the week because of all the MD commuters, but on weekends it's pretty quiet (and safe). I live in Capitol Hill, so I just ride across the 11th St. bridge and I'm right there. Here's one ride that I did: https://app.strava.com/rides/20608656

Getting out of the city proper, Arlington is your best bet. Like you, I prefer to get off the trails when possible, but they're useful to get in and out of good riding areas. I usually take the Custis out to north Arlington and do loops out there. Arlington's streets are much more conducive to getting a good workout, between the hills and the much smaller number of stoplights and low traffic. There are also some good spots out in FFX if you know where to look, and it's easy to string them together into a nice, long ride. Here's one particularly long, hilly loop that covers a pretty wide array of locations out in VA:

https://app.strava.com/rides/11540525

Great. I'll pedal around out there this weekend.

Google up an old cue sheet for the 50 state ride.

If you don't mind a couple miles out, Sterling,Va has some pretty good pave trails. They are technically mup but not heavily used and not the least bit flat(some rises need standing and working at it). My fav and old neighborhood was Sugarland-Run (Google Sugarland run dr. Sterling) If done properly there is enough to link the 4 neghborhoods together to make up over 10 miles of trails in many configurations.

Head through Georgetown and go out MacArthur Blvd to Great Falls, then up to Potomac and take River Rd heading west. There is lots of great riding from there around the Poolesville and Sugarloaf area. Also, from the Shady Grove Metro Station, there are several rides out to the east and northeast starting in Montgomery County. Also some good rides heading east from the New Carrolton Metro Station in Prince George County. In Virginia, I regulary ride out the W&OD Trail to get me away from the congested suburban streets. Then from Leesburg west there is some great country riding. You can skip the in town MUP riding by taking Metro out to Vienna.