I would consider selling, i’m not necessarily saying you should, BUT only hold if you have a very strong belief in the appreciation of this property. 

As a co-host for short term rentals, you may not need a license as long as you're not crossing over into activities that could be considered brokerage activities like handling any contracts, collecting rents, doing any accounting, approving tenants, etc.

When considering 'break-even,' cash flow is included...it's the overall ROI that the property generated for you during your ownership.  

If they push back, you might consider adjusting the rent to reflect the change.

They love the nostalgia of it and wouldn't consider replacing such an important and historical thing.There is no script that will lead you to success in this, but friendly and collaborative will help.

Which is also one of the 3 fundamental needs of a business most often (customers, product/service, place of operation). 

If you’re considering switching careers, pursuing a license could be a great opportunity.

That is the skinniest deal I will even consider.

You can get an ok idea of what houses you're considering might be renting for (at least from a 'listed' price point) to guage how much you may be able to lease yours for.4.

I the understand the wiring for this specific purpose equipment can be considered with the tangible property.