Is your wife concerned about tracking you in case you don't report in on schedule and may have been lost or injured and unconscious?

That SPOT Personal Tracker may do the trick. I'm going to check into that sort of device for my mom, especially on her powered wheelchair. Depends on whether the SPOT device has a fully autonomous mode that doesn't rely on user input or pressing a button.

I see a zillion specialized GPS devices on the market, including for hikers and mariners, but the devices that may be better suited to tracking family members who may become unable to communicate are probably marketed for folks with dementia or Alzheimer's. I've checked into a few for my mom, in case she has another episode of wandering and getting lost, but I don't know the range. I know these are fine for local/regional use, but I don't know whether they're suited to long range tracking. And it needs to be completely autonomous, not something the user has to activate. When my mom has episodes of memory loss she can't even remember how to turn on her tablet or use her cell phone. Anything more complicated than a big red panic button is too complicated. And even then it would depend on the user being conscious.

But it occurs to me those might be adaptable to folks doing long distance solo biking or hiking, as a backup for family or friends in case the traveler doesn't report in for a day or so.