Your stats got me to thinking (danger, danger). I have toured for over 45 years (started young) and I have discovered a few things that help ME determine how fast and/or how hard a given route is.
First, I have found I usually have an Overall Average (OA) riding average of around 8.9 miles per hour. An OA is the day's total distance divided by total time from start to finish including breaks. This is not the same as Overall Moving Average (OMA) which is miles divided by time spent actually moving (clock stops when not moving). Most people use OMA but I prefer OA. The reason is that over the years I have noticed I usually have a paved road OA around 8.9mph regardless of the day's miles, terrain, OMA, etc. I am amazed at how frequently my OA is within +/- 0.5mph of 8.9 regardless of what that day's route threw at me. The gravel OA is not nearly as consistent.
For a few years, I kept thinking Today I will have a different OA due to a moderate tailwind all day, lots of climbing, no sightseeing, etc. but I kept seeing about 75% of the time it is right around 8.9mph overall average. Of course, there may be some obvious known-in-advance variances like a short day with lots of city riding and lots of sightseeing or unexpected variances due to multiple mechanical issues. However, for some reason or another it really does tend to average out most days. Note: I almost always eat breakfast before I start riding so if I eat breakfast after I start riding, it would reduce my OA.
I am fairly consistent in my breaks, climbing pace, etc. so maybe that is why it is usually the same. If I was all over the place, i.e. one day ride hours without stopping, next day stop every 30 minutes, it might change. My OA has slowly but steadily declined as I get older and take more breaks and I have only tracked for about 10 years. Start tracking it for yourself and see what holds true for you.
The second thing I use is the Climbing Index (total elevation gained divided by total miles ridden). The higher the number the more difficult the day is. Rarely do you see a less than 20 day. For me, anything over 80 is a tough day. Your 124 CI route above would not be fun day for me. Alas, I wish could predetermine a "Wind Index" somehow, I would be in heaven.
The third thing I know is that for me, gravel portions add about 30%-35% more time and/or effort compared to a paved route. So while I generally ride 50-65 miles on pavement per day depending on the spacing of services, I only ride 33 to 42 miles on gravel. Since gravel has much more resistance than pavement (duh), I usually ride only about 7 to 8mph while on level ground and since I don't ride a mountain bike with wide tires and suspension, I usually have to go much slower downhill compared to a paved road to maintain control. Plus gravel roads generally are hillier than a paved road.
The last thing that works for me is my personal Overall Miles Per Day Average. This is the overall miles divided by the overall number of days on a tour (not including days getting to/from the tour). This is a personal number you develop over the years but it could be planned also.
For instance, say you did a tour last summer that took 80 days to ride 4,500-miles. Your OMDA on that tour would be 56.25 miles per day on average. This average counts rest days, weather delays, expected sightseeing days, etc. Basically all days from the 1st riding day through the end of the tour not counting travel to/from a tour. As a young pup, I had a OMDA as high as 67 OMDA but even then I thought that was too many miles per day. It was usually around 57.5 or so. Now my OMDA is closer to 50 as I am not time constrained.
The other thing is that once you have a pretty good idea as to your personal OMDA, you will have a more accurate idea as to how many days a given tour will take. The longer the tour the more accurate the OMDA is.
A usual "beginner" mistake is that they think will "average X miles a day" on tour. However, many are thinking X miles per RIDING day (ORDA). If you take any days off, the amount miles you need to ride to maintain the ORDA rapidly increases.
For instance, if you plan for a RMDA of 56.25 on the above 4500-mile 80-day tour, you may very forget about days off. However, while on tour, you realize you need/want a day off (sight see, sick, mechanical, etc.) say about 1 day off every 10 days. Now you have ride 62.50 miles per day for 72 days. But if you unexpectedly get sick on the plane to the start and have to take off 2 more days. Now you have to ride 64.28 miles (4500/70) per day assuming you got sick on Day 1. That is quite a bit more than the 56.25 RMDA you had planned.
Another way to look at it is that if the you planned on a RMDA of 56.25 without thinking about off days but took a day off every 10 days, the tour would take ~88 days.
Conversely, if you had planned on a 56.25 OMDA in the above scenario and got sick, your OMDA would rise to 57.69 (4500/78). Of course, it takes a bit of history to help you get your personal OMDA but once you get one you are comfortable with, it makes planning a little easier such as what day to fly home. To assist the OMDA, I personally always add at least 2 "buffer" days per tour over 1 month long if I have to be at a destination by X date in case some truly unusual happens. Nothing sucks like having to abandon a tour 2-3 days from the end due to a plane ticket.
Anyway, sorry to go so off topic. I hope it all works out for you whatever you end up doing. Tailwinds, John
