When your ceremony is walking distance to the reception, but not adjacent.

I think a map would be helpful for people to get a sense of where things are. Some older guests might not be able to walk .4 miles, so cab information would be good, or maybe you could arrange for a few cabs to be there waiting for older VIP guests?

For what it's worth, all of the elderly guests who are unable to walk will be in wheelchairs, pushed by young people.

I think you're overthinking it. People will map it and either take their own cap, drive, or walk it (most likely the latter). My cousin got married downtown. I followed the mob that walked between the two and ended up there alright. Didn't even think twice about it.

Find a few "point people" who know where to go and can lead large groups in the right direction. That should be enough to ease your mind and help out.

I think you should include the map and written directions.

If I wore nice heels I don't think I'd want to walk half a mile.