[blparent] Potty training update and a few questions

[Pipi]

Hey y'all,
I know this topic has been discussed several times, but hey every kid is different, right?  I'm sorry but I'm sure this will be long. I don't know how to write in short spurts. 
Here's a update on Savannah when it comes to learning to use the toilet. I bought her potty chair when she was about 18 months old. Savannah needs time to adjust to things, so I bought it early. We've talked about what it is. She's watched me and others use the bathroom while we talk about what we are doing. She has a couple of videos, elmo's potty time being one of them. I've occasionally asked Savannah if she wants to go potty. Sometimes she says yes, sometimes no. I've been ok with this. She pooped in the potty chair on my birthday last year, at 18 months, but I'm sure this was just a chance happening that she was sitting at the right time.  While on vacation a few weeks ago, Savannah actually sat on the hotel toilet and went potty. This was a first. We praised her, gave her a quarter. Made a big deal. She tried a couple more times while at the hotel, but never went. We came home and then right back to a new hotel for another vacation. No progress there. When we got home, she pooped some in her diaper and I put her on toilet midway, so she finished in toilet. Again, I praised her, gave her a quarter, etc.
My little sister and her 3 year old daughter were here over the weekend. My niece is wearing panties and is potty trained.  Savannah threw a fit Saturday afternoon because my niece got to wear panties and she wanted them as well. I was outside when this was going on. My sister put a pair of my niece's panties on Savannah. Within a half hour, she wet them. We were going to a carnival that night, so I put a clean pair of panties over a diaper.
Sunday morning, Savannah did not want a diaper. So instead of fighting her, I made the decision, that if she doesn't want to wear diapers, then it's time to actively train her.  I said I'd give it a week of panties and then reassess where she is and either force her back into diapers, or keep going. 
We've been working for 4 days now. She is about 50% going and 50% accidents. I've been having her sit about every half hour. We've moved her potty chair into the living room for better access. She prefers it over the adult toilet, but has sat on it as well. 
When Savannah goes in the toilet, I praise her and reward her. We've used stickers, which was a hit for the 1st couple of days, and her quarters which have been a success all 4 days. I stopped with the stickers because she doesn't really care about them now. 
Savannah has progressed to where if she has an accident, she will take her panties off and go sit on the potty chair. This started last night and today. She isn't verbally telling me that she has to go though.
She has not pooped in the toilet yet. She has a pretty predictable time everyday, but I haven't managed to get her on the potty to do it. When she poops in her panties, I take her into the bathroom and show her that the poop goes into the toilet and not in her panties. 
When she has an accident, I don't get upset with her. I stay calm and tell her it's ok, next time we'll try to make it to the toilet. I ask her where she should poop and potty and she tells me in her toilet.
So I think we are getting there slowly.
I'm trying not to 2nd guess myself or her here.
My questions:
First off, is it ok that she isn't verbally telling me that she has to go? Is this something that will come in time? 
Second, what do I do when we have to leave the house. So far, I've put her in a diaper, but I'm afraid that this isn't helping the training process. That was Monday and Tuesday, which were rough days full of lots of accidents.
We have to go to baseball games tomorrow evening. Do I put her in the diaper until she is better at telling me she needs to go, or do I put her in the training pants that I have? I don't want to buy pull ups if I can avoid them. I do have several pairs of reusable training pants.
Is there anything that anyone can think of that I should be doing differently or also doing to help? Am I doing this correctly, or am I just training myself to take her to the bathroom?
Thanks if you made it this far. It's been too long since I've helped train and it's different since Savannah is my kid and I'm doing this 24/7 and not just while the kid is in my care.
Any advice would be appreciated.
Pipi