Tao Tao Roman 150 exhaust & back wheel problems..

[Christianl1970]

The muffler keeps wanting to come off, finally snapped off at the bottom bolt... sigh. I reattached it with "muffler cement" today... so far so good, but i'm not very optimistic.
Hoping it will hold until I can solve solve my other problem..
Back wheel has about a quarter inch of play going both ways, side to side wobble. The back wheel is bolted on extremely tight, not sure how I'm gonna get it off to keep it from sliding back and forth...
Frustrating because I have yet to identify the exact problem.. from what I have read so far, the bearings seem to be the most likely.
Does that sound right? Is it safe to ride a couple days?