okay - so this is actually related to my Audi - I posted on one of their forums, but I'm not a regular by any means. Hoping someone with some decent automotive savvy can chime in here.

2002 A4 quattro - needs alignment and then learned that also needs control arms replaced. Car creaks and wanders a bit, but otherwise drives fine. Have a trip across the desert (LA to Vegas) and the MCS too small for all we need to take. Unfortunately, I don't think I can get the car in for alignment and control arms before hand (time and $ issue). But, I don't wanna be halfway to Vegas (in the middle of nowhere) and BAM the car stops forward progression. I've had experience in the past with FWD VW's that blow a CV joint and no more movement. But, I'm naive to what a fully busted (if that's even a possibility) vs a worn/needing replaced control arm can do to drivability. Car has 110,000 miles. Appreciate the help.

 

Hard to tell over the internet. My assumption is you are talking about front control arms. I would guess your control arm bushings are worn out. This allows the suspension to move around slightly making it impossible to obtain a good alignment. It should not be a major problem and should not totally fail leaving you stuck on the highway. However, I would get them replaced as soon as possible (after your trip).

 

Get Powerflex Urethane bushings

 

thanks, makes me feel a little better.

 

definitely a consideration for the MCS - but the audi - it's just basic transportation. no more $ then necessary to keep it safe and running down the road.

 

The bushing is a possibility. I think those can be replaced separate from the control arm. Another possible is the ball joint which is integrated into the control arm, or maybe but less likely, the control arm is bent (?).
as quikmni said, it's probably driveable as long as it is not noticably wandering all over the place.
When the car is parked, give a hard push and pull on the top of the tire. No looseness, your probably OK (In my non-professional opinion)