I enjoyed the challenge, thank you. I also confirmed that I am motivated by having concrete goals AND by the lovely medal. At 66, you'd think a person would be "self-motivated" but we are all made differently. I do have some suggestions, because that IS how my mind works, and should not be construed as criticism.
-I think it would be helpful to make the "rules" abundantly clear. It hurt my heart to see how many people were so distraught because they were "behind." I am personally, in my more 'mature' season of life, USUALLY able to give myself freedom if things aren't spelled out. Perhaps specifically saying if, or if not, participants are free to take off days and simply extend their 40 days when they are able to get back on track. You could even suggest that some may choose to take the Sabbath off. I personally missed two days for being sick and one day for travel. I intended to tack those three days to the end of my 40, but was able to make up the distance pretty easily, so didn't need to. But the freedom, in my own mind, to do so, spared me any real discouragement. Make it clear that people who start late in the challenge are in no way expected to "catch up" with the larger group, but to proceed to do their 40 days from their start day. (I was confident in this, but saw several people on the Facebook page, despairing of ever "catching up" to the group and, so, were already discouraged! I do think that a large percentage of those of us who participate in a virtual event like this are self-selected for being more easily discouraged. My self-disciplined, athletic husband, doesn't need to be encouraged by any external source!)
Beyond the check box, I would like to see room in the provided booklet for writing down our distances each day (maybe even two slots, as sometimes I'd get data on my treadmill in the morning for part of my mile, then convert additional "steps" data at the end of the day for my long walk to the mailbox and that trip to the grocery store (I learned that I routinely walked a mile at the store!) Then add space for the ongoing total distance. I've got scribbles of all this squeezed in my booklet. You might even consider leaving blank lines for a person's thoughts about the Scripture reading for the day. I do understand balancing printing costs for a small business, so these are just suggestions.
Perhaps collaborate with a reliable, Bible teaching source, to add some short explanation to the Scripture readings for the very new (or not) believers. And/or a short devotion. "Our Daily Bread" is a beautiful resource that offers a small devotional book at no cost, or they are happy to accept a donation. Arranging to include one of their booklets in your package would be amazing. (They are quarterly, so have dated, daily readings, but since your challenges have 'official' start dates, it shouldn't be much of a mismatch. -Scripture is a living thing, meant to impact real life and I think devotionals illustrate that well, especially for new believers or those who come from a church background that doesn't encourage a "relationship" mindset on their walk with the Lord.
Maybe add a section of tips to getting started. Because I live on the side of a steep hill and have ankle/foot problems, I bought an inexpensive treadmill. At first it was just awful- my stamina and balance was terrible (mine does not have any uprights to hold onto.) So I put a heavy chair nearby to hold onto, which helped immensely. But beyond that, I found virtual running videos on YouTube that are wonderful for tricking my mind into feeling like I'm going somewhere (usually in beautiful places!) I can pick a tree or a rock on the path ahead and tell myself I won't look down at the distance readout on the treadmill again until I reach that rock. (As opposed to staring at the readout!) Even though I walk on the treadmill, I found the RUNNING videos much, much better. Obviously, watching a program or listening to a book on tape is also a good distraction.
One last suggestion for something to record in our booklet, might be a record for where we've walked during the challenge and/or interesting things encountered while walking, an interesting animal, a beautiful sunset, ran into a new friend, or felt the Lord say something to us. - Mostly I've walked on my treadmill or at the grocery store but, because of the challenge, I made myself walk even while on vacation and other travel. I walked in 7 different places over the 40 days.
Thank-you for, while trying to make a living, you've chosen to point people toward the Lord and getting couch potatoes, like me, up and moving. I haven't lost any weight yet, but have noticed a nice increase in my stamina.
~Blessings, Carol V.