Hi @Annette76 very sorry to hear about your change of circumstances. I wish you luck in figuring things out.
I highly recommend thinking about sticking with your original idea of using the above the garage apartment as the short term rental.
First of all, if you do the main house, there are lots of other fish in that pool, if your surrounding neighbors are renting out larger places too. Larger groups mean a lot more work.
I often feel lucky that my place is a one bedroom with a capacity of 4. It keeps things much simpler, and I mostly attract couples or families with young kids. Lots of people may want to come to your area, but maybe don't need a larger place, and they're not going to want to spend the money on more bedrooms than they need. The smaller place means less work, fewer issues (like parties, extra unregistered guests, etc.), and you're a big fish in a smaller pool, if most of the places around you are larger.
I'm an onsite host as well. I make that very clear in my property description, and also make very clear that my life goes on even with guests in residence, and that they will likely see me out and about on the property. There's plenty of space, and the boundaries are clear. I don't want to feel like I have to hide out when guests are around. Being onsite has helped in many ways- I don't have people sneaking in extra guests or pets, or trying to throw parties.
Good luck! Kia