T.H.
We used plastic pants for potty training out and about. You still need to carry plastic bags and extra panties around, but it does help to catch the liquid so you can make it to a bathroom. They wash super fast and well in the sink or the washer and in an emergency can be dried with paper towels in the public bathroom to be worn again right away.
That being said, I waited until my kids were 3 to potty train because I knew they would be totally ready. After 3 days we didn't have any issues and very rarely had any issue in public or at home. So it sounds like if your daughter is almost 3 it will probably go pretty well for you and hopefully you won't have to worry!