I'd say that it is typical for some kids to travel with others, as some kids have parents working, unable to take off work, other kids who can't always come, etc.
Big things:
1. Make sure your mom is okay with you traveling with another adult and being under their supervision. You can't really consider it unless she is okay with it.
2. Make sure it is okay with the gym. Some gyms require that you be with your own parent or adult guardian, depending on your age. So they don't allow kids to travel in groups with other parents.
3. If both of the above are okay, make sure you've secured said family before you commit to a team.
4. Ensure that you can afford the travel, lodging, food, etc. and make sure you've discussed that with your parent. Yes, you may be traveling with someone else, but you are expected to pay for a portion of gas, your own food, etc. People do not mind helping out, but they START to mind if (for example) every time Becky travels with them, they end up paying for all three days of her meals because her parents did not send her with enough money. Or Becky's mom was supposed to reimburse for hotel but did not.
5. Know that when you are with another adult, you need to be okay with listening to them. I've seen so many kids at comps think "Becky's mom isn't my mom, so she's just TAKING me to the comp and I don't have to listen. I can be out at the pool all night if I want." Nope. You need to obey the adult you're with because they are responsible for you for the weekend. Depending on age, this may not be an issue.