Lol, in your first few sentences I thought you were talking about my 25 month old! ; )
I have to stay 2 steps ahead of him to avoid him grabbing the keys, phones, remotes, or what ever is out. He is very high energy and inquisitive. When he's caught in the act he flashes this "how can you be upset with me?" smile, already trying to manipulate. And he will cry and scream to get his way at times and I just don't give in.
I learned with my oldest that when he began to throw a tantrum at home to calmly walk (or carry him if he refused to walk) to his room, explain that he could come out when he stopped crying, and close the door. He wanted an audience and when he realized he didn't have one he stopped. By the third time I took his hand to take him to his room he stopped immediately and he thankfully never threw another tantrum. His sister was harder, being very theatrical, but this eventually worked with her as well since she also wanted an audience. With her I experienced the in-store tantrums and we left the store or wherever we were and I learned to not take her to the supermarket or anywhere we would need to be longer than 10 -15 minutes until she was a little older and more mature. She didn't like having to leave places so when I reminded her to behave the next time she usually would. And I learned to be consistent, as hard as it was and is for me to do so at times.
Toddlers get frustrated by not being able to communicate their needs and wants to us, they have lots of words in their heads but don't always know how to put them together to communicate, they get hungry or tired and then cranky because they don't like feeling that way. They also see things they want and can't understand why they can't have them, so I learned to do expedited shopping, and not linger in stores. I took her to restaurants when there weren't so many people between 2 and 4, and made it special to her by us both dressing up, so it would be something she wanted to do and less likely to cause a reason for us to leave. I let her know that because she was unhappy it wasn't OK for her to throw a fit. Basically, I had to teach her how to behave because she didn't know, and am doing the same with my youngest now.
After the tantrums with the older ones and now with the youngest I get at eye level and acknowledge his unhappiness, and try to find out the reason. Whether he can give me a reason or not I let them know I understand his frustration and unhappiness and how it's hard for him to tell me, but tell him that we can't scream just to get our way. People will say he doesn't understand all this yet, but that is why I'm teaching him. I don't want him thinking he can have his own way and becoming increasingly manipulative when he's older.
So, I would say don't coddle at home or away, don't assume she knows how to behave ~ teach her, have consequences you've explained in advance and carry them out consistently.
Above all, hang in there! : )