I think using one of the Garmin programs - either BaseCamp or MapSource - is the most hassle free way to get your routes on the GPS. I used MapSource for a long time and then switched to BaseCamp when it came out. It took me quite a while to get proficient with BaseCamp probably because I was so used to the other.

I've gone back to using MapSource because of a feature missing in BaseCamp (unless it's been added). I prefer to map by using Intersections as waypoints. First, they are invisible to the Garmin - no announcement at an intersection waypoint. Second, if I want to take a back road that is missed when I select my intersections, then I pick an intersection on the back road to force the route to go that way.

I just find using intersection waypoints an easy way to map. Also, I set the Garmin Recalculation Mode to Prompted. That way, if I get off route it doesn't Auto recalculate and I can easily get back on course. (Garmin 550)

 

Couple questions; This is my first venture into using my zumo to its full potential. I've never done any custom routes before. So after I create a route and load it on the GPS, when using a custom route, what will the GPS do if I go off route? Will it route me back to my custom one? Or will it attempt to modify the custom route? What will it do when I set it to a custom route, and I'm nowhere near where it is? Will it direct me to it and then begin to follow the route? Sorry, lot to learn here...

 

What it does if you go off route depends on the Recalculation Mode. In Prompted or OFF, the intended route remains visible and the icon indicates your location allowing you to get back on route without directions. In Auto Recalculate, it (my 550) recalculates and heads me to my final destination by what's chosen (fastest, shortest
and avoidances). When that happens, you have to stop Where To and reselect your route in the menu.

If you are a distance from the start of your selected route, it will provide the option of providing directions (Navigate to Start) or not to the START of your route. Selecting to Navigate is what I usually do. It takes you to the start using shortest or quickest and the Avoidances that are selected. Quickest is usually better than shortest cause shortest can get you on some real cow paths.

If you add a gas station, hotel or other stop as a Waypoint, it will alter the route to get you there and then back onto your original route.