I'm installing a garage on the side of my house furthest from the electrical box. I don't want to trench the entire distance (60 ft), so I am planning on running conduit along the exterior of my home to the wall nearest the garage. From there I would dig my trench to run to the garage (~ 10 ft), and transition from an above ground to a below ground installation. I'm planning on a 60 Amp circuit to power the garage. EMT can be placed underground according to 358.10.A.1. If I read correctly it only needs to be buried 6 inches, where I need to go 18 with PVC. Am I understanding this correctly or off base in my analysis? What would be the recommended choice in this instance.
If you do use EMT outside or in ground you will need to use compression couplings listed for wet/ damp locations, it will need to be secured every 10' and within 3' of the boxes. EMT would require 18" burial depth. Knowing you are going from 1 end of the home down then back up you will have more than 360 degrees of bends so conduit bodies or boxes will be needed to provide pull points. I will usually use conduit bodies to go around corners makes a tight turn with a LB then further away I will use another to make the turn to go in the ground LR or LL with 90 deg sweeps in the bottom of the trench at both ends and a LB or box to enter the building (box being a exterior disconnect). I think you might find schedule 80 PVC a bit cheaper and easier to work with than 1" or greater EMT.
There are a few things you need to consider before running a long feeder and it seems you have at least given it some thought about method and materials.
First you say:
I am planning on running conduit along the exterior of my home to the wall nearest the garage.
The word "to" bothers me. Shouldn't it be "on". In other words you can't just run conduit on the ground. Conduit has to meet code requirements on securing conduit to something that doesn't move. So it needs to be strapped onto something so it doesn't move freely. There are different strapping requirements for each type of conduit and these can be found in individual articles in Chapter 3 of the NEC.
Also NEC code only allows 360 degrees of bends before adding a pull box this can be a variety of different types of boxes, condulets, etc. You will find you will need to follow these rules when you are trying to pull conductors as a 90 requires around 10 time more resistance than a straight pull.
You can bury EMT but most contractors I know won't do it. Depending on the PH of your soil could cause the conduit to erode, sometime in less than a year. PVC is you best bet. Also most good contractors will always bury conduit at least 18" in the ground if possible. The reasoning being that anyone accidentally cutting a 60A underground circuit is not an experience anyone enjoys.
Good luck on your project and stay safe.