It's easy to draw a route on ridewithgps.com. You might need a free login name.

You tell it a starting location, then click on a road to draw a route to that point, and then click another, etc. You can undo or redo to try different roads. Then click Save and give it a name.

Pull down the Map list at the top right, and checkmark Terrain. Then when you zoom in, it shows contour lines every 40 feet, darker lines with elevation every 200 feet, and shaded mountains.

For example, I found this 100 mile route near LA. See the red elevation graph at the bottom. You can hover over it to see the grade and elevation at that point.

Even better, drag a section of the graph to zoom in on that part of the ride. It gives you average grade, and elevation gain for the climb, and the distance in miles of that segment, on the Metrics tab at the right side.