It says the minimum workday is 10 hours. Who would retire at 50 and want to spend 2 months intensely working 10 hours a day? You obviously had the work ethic and happened to find the right line of work to both afford an RV and retire at 50... why go back to what is the most entry level of entry level jobs to get a little extra cash? What would you use the cash for? $13/hour * 60 hours a week * 8 weeks = $6240 * 30% tax = $4368 for your entire duration (plus free utilities). I don't see how that's worth it. That's less than two weeks of an 8-hour-a-day job for pretty much any professional in New York City, and they get a 401k, insurance, etc.
I'm not sure I'll retire at 50, but I am sure I won't be working 60 hour weeks out of a van. Unless something changes dramatically, of course. You never know.
I think there are two types of folks. In one camp you have those that retire early because they are wealthy and buy an RV to travel. On the other hand there is a segment that is normal folks who are sick of the rat race or got laid off and have enough money to retire if they live extremely frugally and living in an RV is a way to save money and forgo the expense of a house.
I imagine this Amazon thing is attractive to the latter type of situation.
Physically demanding doesn't necessarily mean heavy. Moving at a rapid pace for extended periods is considered physically demanding.
If you're in regular shape at 50 or 60, this is tiring but absolutely doable for a few days or weeks. I'd even argue that it's healthy to physically push yourself.
But someone else noted that these temp workers aren't expected to hit the same output.