I started using MapMyHike in May this year, seriously in June, so I have nice data I can look at to see what it is I've actually done with the silly horse. (One catch: I track most of my rides, regardless of what horse, so my total mileage for a week that MMH shows may be slightly over.)
I can say with reasonable confidence that I've been riding 15-30 miles on any given week. I was not happy with the level of conditioning we achieved last year and wanted to improve on it, so 25 has been the rough number I've been aiming for this season. Per Mel's conditioning post earlier this year, I knew I wanted to aim for 1-2 long/moderate trot rides and 1-2 shorter/speed rides. But.. I didn't actually start really DOING those shorter rides until August. Hindsight! The reality is now that I'm getting in maybe one long/moderate trot ride, two speed/short rides, and one to two casual trail rides that don't really qualify as conditioning, just mileage.
I think that reality is probably where we'll settle for right now. A qualifier: moderate trot really ends up meaning 'whatever the fastest speed is she'll give me', which brings us close to a 5mph average on longer rides.
*April rides (TrackMyHack): primarily 3-3.5mph
*May rides (TMH again): primarily 2.5-3.5mph
*June rides: primarily 2-4mph
*July rides: primarily 3.5-4.5mph, a few faster rides up to 5mph
*August rides: way all over the place! primarily (kind of) 3.5-5mph, a few faster rides as I started short/fast rides
*September rides: primarily 3.5-5.5mph, a few faster rides up to 6.6mph!
*October rides: primarily 3.5-4mph. We didn't ride as much this month (or I didn't log what we did) since I knew we could start tapering off for the winter.
*November rides so far: all over the place with a bunch of not-tracked rides too.
Our flat section of trail is around 3 miles in total. It's pretty heavily populated with hikers, dogs, and the occasional illicit bikes; my tendency to go out fairly late luckily means that most are gone by then. This is mostly where I'm getting the speed work (5mph+) in, with no hills involved to slow us down. The footing is excellent and the trail is such that I can see hikers before we're right on top of them.
3.5-4mph is reasonable when riding with friends. I don't generally count those as real conditioning/work, yet I have no desire to take those out of the equation. If I were always riding on my own, I'd aim to get our lower speeds up and default into something quicker. However, I genuinely enjoy these rides with friends, and at least one friend is working on conditioning her horse in hopes of an eventual LD!
My current goals: amp up our 'default' trot to be closer to 5mph. Move our Big Trot closer to 7mph. (Both of those on the flat-speed sections, since my perspectives are all skewed when you add hills.)
My goal for this past year was to get that 6-mile loop of ours done with a 5mph average. When I started tracking, it was a 3.5mph average, maaaaybe 4. Now? Nearly 5 when I'm not pushing her for speed, 5 when I am. Improved!
I'm going to continue to aim for 1-2 speed rides as weather permits, ideally one longer one, definitely adding that longer one in when spring comes around. I know there's value to riding less often.. but I know I need to hop on the pony regularly for a mental reset, so as of yet I am not comfortable planning to cut my ride days further. Shorter rides, or just meandering around the barn? Both totally acceptable and I will feel no guilt about not riding her harder or longer during the week.