I think it depends on the year of your Vanagon; for 83-85, I believe the A/C condenser is attached to the frame of the vehicle so radiator can be dropped on its own; for 86+ the A/C condenser is attached to the radiator so the pair will drop together.
Not 100% sure but remember reading this somewhere when I needed to drop my radiator in my 85 to replace radiator fan (turns out I thought the job was a little beyond my skill level and took it to my mechanic....that's why I don't know for sure.)
BTW....if you are dropping radiator this would be an excellent time to replace radiator fan; they are 30 years old or so and not gonna last too much longer (as I found out the hard way on a long roadtrip 1200 miles from home and hot weather and big mountains looming); fan motor bearings eventually wear out and are not readily able to re-lubricate, or at least reliably.  Listmember Mark Drillock did some great research and experimenting and came up with an excellent solution for those of us with 85 and older vans; I did exactly what he recommended and it works perfectly; my mechanic was likewise impressed by this novel solution:  

http://www.thesamba.com/vw/forum/viewtopic.php?t=601997

Finding a new radiator fan for an 83-85 Vanagon is virtually impossible and extremely expensive; found one vendor that "maybe" had these ($575); so Mark's solution for $75 is the way to go.

Rich
San Diego

      From: Kevin P Gilleran <kevin@GILLERANENERGY.COM>
 To: vanagon@GERRY.VANAGON.COM 
 Sent: Thursday, September 21, 2017 12:15 PM
 Subject: Advise me on a radiator change
   
Hi,
Chiming in on the radiator change with a related question.

If your van has air conditioning does the condenser also need to be removed
at the same time as the radiator or can you work around the condenser and
hoses and leave it in place?

Sincerely,

Kevin P. Gilleran