Is there a way to change the outer CV boot (closest to the wheel) without taking the whole axle shaft out...? Would attempting this be more trouble than its worth...?

 

To get to the point of being able to replace the boot, you are just one prybar away from removing the entire half shaft.
Might as well pull if off and inspect and clean that joint before just putting a new boot on. It may be loaded with crap. You'll do a better job on a benchtop.
Might as well replace the dif seal at that point too. They're cheap (under $10).

 

I wouldn't bother with just a boot when a remain half shaft is inexpensive and you have to remove the half shaft go do the boot anyway. X2 on what hunger said. New diff seal too.

 

Get a new shaft AND a new boot, replace the entire shaft and then replace the boot on the removed shaft for a trail spare.