APRS Coverage
Don't know
Voice Cellular Coverage
Spotty, may not work at all
Data Cellular Coverage
Decent, workable
Cellular Provider
AT&T

Flagg Mountain is a great 4 point short hike (or drive-up) summit located west of Winthrop, WA.  For a day trip, it could be combined with Goat Peak Lookout summit W7W/OK-107.  

Directions/Access:

Heading East over the Cascades Highway 20, turn left onto Lost River Road heading North toward Mazama.  In .4 miles turn right onto Goat Creak Road.  In ~2 miles turn sharp left onto Goat Creak Road / NF-52.  After driving on NF-52 for 2.6 miles, you will turn left (there should be a sign pointing toward Goat Peak Lookout).  In 1.3 miles, turn left onto smaller road.  I was able to drive a Corolla in .1 mile on this road to a nice open parking area.  If you have a 4x4, you may continue on toward summit. 

Hiking from this parking area was 2.6 miles RT, and 573 feet of gain.  To hike/drive, continue straight on the main road.  Via the map, it looks like there is a circular loop...but the west side of the loop was blocked by trees.  In ~1 mile, you will arrive at the green gate.  There are no signs posted, and I walked around the gate toward the summit which has two radio/cell towers.  

The summit is fairly open with some trees for antenna and/or mast.  Views were great looking toward Highway 20, the Methow Valley, NW toward Goat Peak, and NE toward Fawn Peak.  I leaned an antenna mast against a tree, and using a random wire antenna quickly made 6 contacts on 20m.  Tried calling a few times on 146.520, but no response.  Cell phone service (AT&T) worked great on the summit, and was able to self-spot.