Check out www.garmin.com. I have the Garmin e Trex
& case. I just tie it onto the front of my saddle. Simple to use
& it will give you a pretty accurate idea of your speed, ave. speed &
miles as well as keeping you from getting lost when you start trekking out for
those longer rides in unknown territory.
I'm fairly new to endurance also and
started as you plan with CTR & LD. Now up to 700 mi. endurance &
still consider myself a novice. Read, read, read everything you can on
conditioning, feeding, electrolytes, cooling, leg care, shoeing.
Practice your pulse checks & listening to gut sounds. What does your
horse feel & look like in different conditions and at different
distances? What does he eat, when does he drink? Tune in to
everything. I've had pleasure trail horses for over 30 yrs. but I've
learned more about horse physiology in the past 2 than ever before &
I'm still trying to put it all
together.