They could self manage for several years, using the rental income, until the next phase of their retirement.If they have a decent amount of financial discipline, they may want to get a HELOC now before they build to get the most favorable rate.

Maintenance and potential repairs will also require a long-term financial plan and setting aside a contingency fund for such expenses.The steady cash flow, appreciation over time, and tax benefits can make a meaningful difference to your wealth in the long term, especially with the principal paydown on the mortgage.However, if managing the property from a distance feels too burdensome, or if you’d prefer the certainty and flexibility that comes with having less debt (especially given the high mortgage rates), selling and using the $100,000 in equity to reduce your loan for your next home may be the smarter move.

Where to get the most recent and accurate data for things like:Unemployment dataPopulation growthJob diversity and top employers in the areaVacancy rates (eg huduser.org)Property taxes and jnsurance costsI saw bp pro and reventure and a bunch of other websites provide some of this data, but i wonder how accurate and recent it is.

You can find out nightly rates, occupancy and amenities.

The interest rate is not special nor is the 20% down (80% LTV).  

You would end up saving the higher interest rate on the HELOC as well as closing costs.

I agree with William that the rate you have is probably better than you'd be able to get moving into another property with rates where they are today. 

Also, I would look at rental rates to property values to determine if any areas are around the 1% rule.

Definitely something to clarify upfront...If you’re replacing with another restaurant, it should be an easier transition since the setup is already in place.Your biggest risk is vacancy $450K/year is solid, but if you ever need a new tenant,  ensuring the lease rate is sustainable is key! 

Be grateful for the screaming deal you had, adapt to change.