Need th stop at Km21 Nogales?

For those who cannot walk across the border in the days prior to actually crossing you will still need to stop to get your FMM and clear Customs. Personally we drive to 21 and do the work because we find it less of a hassle than driving to the border in advance and walking over and then walking back - and having to stand in line anyway. We stop near/in Amado, AZ the night before crossing and get to the border almost as they open and then are among the first to 21 so no big deal. Border crossing with vehicles can be a hassle in MX no matter where you cross - vehicle permits - immigration papers - insurance - customs - etc. We just crossed from Canada to the US near Ogdenburg,NY and it took about 1 minute total. When we crossed into Canada at Sault Ste. Marie it took about 1/2 hour in line - but only passport check - no paperwork or permits in either direction. No forms to fill out. No fees. No stickers. No problem. We still love going to MX so we do what must be done - we plan for it so it is not as much of a hassle once you get used to after a few times.