If it is "darty", the toe setting is probably out. Something changed if you can notice it. If the car is wandering, it could be heavily grooved roads from heavy traffic.
Wonder why it won't fit on alignment machine?
Try a place that works on trucks, they should have room to align. Sometimes the old truck shops are cheaper.
You could just "set the toe and go" or get a full alignment, either should work. Bad toe will eat your tires. Toe-out will make your car wander. Too much toe-in or toe-out will scrub your tires.
My preferred spec is 3 degrees of caster, 1/4 degree camber (top of tires closer), and 1/16 to 1/8" toe-in, both sides the same. Crowned roads didn't make my car pull or wander, wear was nonexistant, got 88,000 out of a set of Nitto 'NT255' size 235/60-15 tires on our '83 Regal.
Alignment specs are like opinions, everyone has one.