@Christy Osterkamp
We have a few properties in which we do basement STR's with a private entrance. A couple things are important for them to know.
1. Make sure you are very clear this is a lower level unit of essentially a duplex. Don't have them caught off guard on what your unit is or is not.
2. Noise can be a factor is not properly insulated in between floors. There are some easy ways to help with that. If there is connecting door to the units, put up a noise cancelling curtain or insulate the doors. I went as far as adding in blown in insulation to the ceiling. Not 100% necessary as you can still hear people walk from the vibration, but people talking has been almost eliminated. Also, insulate your vents openings. It can help tremendously with noise dampening.
3. Temperature control. This is a very common "issue" that comes up. Again, need to make it very transparent that you keep the temperature at certain levels such as 68-70, etc. Make that very clear in your description. Provide space heaters for each room in case people want it warmer.
4. Make sure you let them know this is not a party house! We make it clear in our description, when they book it, check in instructions, welcome book downstairs. This is your home and people need to understand that. Knock on wood, we've had really no bad experiences with regards to parties because we follow our steps to ensure it won't happen.
Let me know if you have other questions, good luck!