THE trailguide for this area is:
http://www.sorbachattanooga.org/index.php
A GREAT local source for current trail conditions and getting together and MTB'ing is:
http://www.nationalmountainbike.com/index.php
NOW, assuming you're in Rutherford Co. somewhere, the best, closest, weather-resistant, flexible trail system is found at AEDC.
It's 14-mile loop with many many ways to make it shorter or longer or to limp back to the truck. I ran it twice Monday and it was in EXCELLENT shape.
Montgomery Bell has been closed by conditions. Hamilton Creek will never close, but that doesn't mean you should ride it. Easy for me I never ride there.
Fall Creek Falls, Franklin State Forest, St. Andrews Race Course, Sewanee Perimeter Trail, AEDC, Tim's Ford, Defeated Creek--those are all trails to the East of the Boro and sometimes rideable when others aren't.
Lock 4 and Chickasaw Trace are great rides, but more WX sensitive than those above.
Lots of discussion and current reports at NMB link above. Check it out.
I expect, per this weeks weather, that AEDC will be the only rideable trail this weekend. I find AEDC to be a good beginner to intermediate trail. No rock gardens, some roots, no big climbs, some fire roads, and lots of great twisties--especially going counter clockwise. 
I (go) ride Sundays and Mondays.
Directions are everywhere, but just in case someone can't manage two more mouse clicks:
Take 24 East to exit #117, go right
Continue to UTSI road, about 2 miles past Gate #2.
Take UTSI road to 4-way stop, go LEFT on Lakeshore.
Go about one mile to AEDC Saddle Club Parking on left.
Maps at kiosk.