Most of the vacation rental guests I talk to want a whole house/apartment to themselves -- they want privacy too.
Is there any way to divide the house into two units with a locked door between them? Then you could safely rent out the second unit as an apartment either short term or long term. This, of course, would involve some cost for renovation, installation of doors and perhaps putting in a small second kitchen. You'd need to check local zoning laws and figure out if it's even legal to do that in your neighborhood.
Maybe instead of a vacation rental you should consider a B&B. B&B guests expect to share common space so they wouldn't need a separate unit. But a B&B requires some extra work on your part to make those great breakfasts, and if you go to work every morning, this might not be practical unless your daughter could help out. Ditto for checking on zoning laws if you do this.
The other option is to take on a boarder or two -- long-term renters who rent one of your bedrooms. You may include them in your family meals or you could give them kitchen privileges. You'd want to vet them carefully since they will be part of your household. Check your local ordinances on the number of unrelated individuals who can live in the same house. You'd advertise this locally as "room for rent" or "house share" -- it's common in university towns, I'm not sure about the rest of the world
Best of luck, it sounds like you are thinking creatively to figure out a way to hold on to the house.
The first thing to check on is the local zoning. Most of us are able to rent out our vacation homes because we rent the whole unit - in most places it is equivalent to a traditional lease - just for a very short period. So our rentals are covered by the same zoning permissions that let you rent a house by the month or year (allowed almost everywhere).
But renting just a room, or part of the house typically puts you in a boarding house classification, or if you provide meals, a Bed and Breakfast classification. Most residential zoning will not allow this, or requires a variance from the town zoning board. Same goes for sub-dividing your house. If there are two entrances and the living space is blocked off, you have created an apartment - which is usually restricted by zoning laws.
From a safety viewpoint, we've found renters to be a pretty safe group to work with. You'd need to screen by telephone to get any real level of comfort, and keep the group sizes very small (2-4 people) at first until you get a feel for the processes. Personally, I'd feel safe, and you might as well - but your daughter's concerns about her own safety and privacy would be paramount in my mind.
If you want to give it a try on a very casual basis, check out AirBnB (a competitor to HomeAway, but they have a fairly different business model). They are targetted specifically at people looking to rent out access to their homes, and do a lot of advertising in high-end metro areas like silicon valley and the NYC tech crowds. AirBnB even requires prospective renters to fill out profiles and allows homeowners to see reviews about the renter from previous hosts if the prospect has used AirBnB for rentals previously. Their methods of setting up the rental are kind of byzzantine and restrictive, but we've had renters through them before and it does work. Oh, and AirBnB is free to list for homeowners - the renter pays the finders fee.