Not much else to add on the retirement plan side of things, but my resting heart rate is in the mid-high 30s (I'm 51). But I'm in pretty good shape (biking a lot, running marathons). Although should also note that my doctor this year has kept me coming in for tests just to rule out bradycardia.
Many of the retirees in our area seem to work a few hours each week at part-time jobs in the area, less for monetary reasons and more for social reasons, I suspect. Given the labor shortage I would imagine finding part-time work wouldn't be a major issue, but not sure that running a cash register at a local conbini for Y1000 an hour is what you had in mind...my father in law worked about 10 hours a week at a bicycle parking spot near the station for quite a few years, which he actually enjoyed except when it rained...
You're actually planning for retirement, which I suspect puts you ahead of the vast majority of people...