Well, if I had read the book, I would have known the following.
One of my favorite tips for editing in a bumpy cockpit is to tap your finger on the search box, which will put your cursor at the end of the line, ready for you to start typing. Tap and hold your finger in the center of the search box until the "bubble" appears. This is a magnifying glass designed to help you see where the insertion cursor is beneath your finger. The problem is that it's so high up on the screen, it gets in the way. TIP: While holding down your finger, drag the bubble down to about halfway down the screen and you'll be able to see the insert cursor clearly up in the search box (ignore the bubble). Now if you drag your finger left or right, you can scroll through your route and then let go when the insert cursor is at the exact point where you want to continue editing.