Unless you were in a place with no serious population of locals, the best way to keep renting out your furnished vacation rentals is not to chase a few nurses for a couple of months.

there are still a lot of people looking for rooms and apartments and homes.

I am mostly full, and the average furnished rental seems to last a number of months.

put your place is both rooms for rent and as the whole place on the following sites:

Craigslist, which is probably half the rental market. There are several categories you can stick it under. Make sure you also try to put it in neighboring areas to attract more people

turbotenant. They will stick your ad in many places. Note that some of the enquiries will not answer your responses. If you advertise rooms, some of the places they put it will interpret it as an apartment and lead to confused enquiries. Just explain that it is a furnished room for one and see if they're still interested

if you are dead set on getting back to short term rental quickly, which I think you might be shocked how bad that will be this year, then just make your Lisa with them month to month so you can push him out