Preparing your children for the death of a loved one. The line between honesty and too much information

Sadly, my grandpa's wife, Miss Juanita; the woman who has filled the position of grandma for us, since the passing of our grandmother when I was 8, is very near to death. This is the first family member to pass since our children have been old enough to really know or understand what is going on. As we were on our way to the hospital today, we explained to them that Miss Juanita was very sick and that she would be going to heaven to see Jesus soon. So we told them we were going to the hospital to support Papaw B and say goodbye to Miss Juanita. They each said ok and didnt say much else about it all the way there. They went on talking amongst themselves and playing with their toys.
Once at the hospital, we visited with family, they watched cartoons in the waiting room, and then we took them back to tell everyone bye and give Papaw B hugs. At first we weren't going to take them back, but they were asking and asking to see her. I kept telling them she was sleeping and she needed to rest, but began to doubt my mothering choices.
 (Incident #1 of asking myself the questions... Are my children old enough to experiance this? Should I try to make this a rosey situation for them or give them the details and let them learn how real death is? How much detail is too much detail?)
They seemed to handle seing her very well. She looked to be very peacefully sleeping, they looked on from a distance and said bye to my grandpa after a brief minute, but did not want to hug Miss Juanita(which was fine). As we left, Leah and Carson were very quite, and Ethan said nothing at all. Once we got into the car and got everyone settled Leah broke the silence with her question "Was she already in heaven mommy?" I answered her by telling her she was just sleeping right now(truth) She was ok with that answer and said "ok" Ethan by then almost in tear just starts rattling off the questions
(Incident #2 of asking myself the questions... Are my children old enough to experiance this? Should I try to make this a rosey situation for them or give them the details and let them learn how real death is? How much detail is too much detail?).
 He was just spilling them out... How do you die? Will it hurt when she dies?  So I am trying to answer his questions honestly without scaring him to death, or giving him too much detail. I tell him that for Miss Juanita it wont hurt too bad, she is just sleeping now and then she will go up to heaven. Then he asks "How does she know when it's time to die?" So I told him that because she loved Jesus and she was going to heaven, that Jesus would come to her while she was sleeping and tell her that it was time to come to heaven and she would just stop breathing and go up to heaven(this was my best attempt at giving truth and deatil in what I thought was appropriate doses) He was very quiet for a while after this....
(Incident #3 of asking myself the questions... Are my children old enough to experiance this? Should I try to make this a rosey situation for them or give them the details and let them learn how real death is? How much detail is too much detail?)
Kevin asks Leah if her bicycle is working better since he fixed the tire, kinda trying to change the subject and She says "yes"and then says "I wonder if there will be bikes in heaven, I would like to ride my bike with Jesus" This was follwed by a discussion about how wonderful heaven would be and then everyone went back to talking and playing with their own things. Much to my relief.
Ethan has asked a few questions since we have been home this evening, but they havent really mentioned it all that much. I know the next few days will be filled with grief and joy for all who are involved and I want to properly prepare the kids for what they may experiance, while mainainting their innocence but also respecting their need to grieve and ask questions.
 So here I sit... asking myself... Are my children old enough to experiance this? Should I try to make this a rosey situation for them or give them the details and let them learn how real death is? How much detail is too much detail?
Here's the honest truth. I have no clue what the right answer is. One second I feel like allowing them to experiance all things honestly is a great thing, the next second I feel like I am giving to much detail and a simple yes or no would have sufficed. I've tried to remeber back to when I was 8 and my grandmother passed and how my parents handled it, but that was a totaly different scenario(she passed unexpectidly) and I was a little older.
 I am forever thankful that it is made a little easier because we can rejoice and assure them that she is going to heaven to be with Jesus, her glourious Lord and Savior, and there will be no more pain, and no more tears. I hope and pray that even through tradgedy they can see the reality of God's love and care for his children and that it may bring them one step closer to knowing him as their Savior.
Yet, I still find myself asking "What is the line between honesty and too much information?" "How can I best prepare my children for the grieving process that is to come in the next few days?"
God gently reminds me, as I sit here typing, worrying, wonder... My Grace Is Enough.
 The responsibility of parenting can be overwhelming at times. We all want to shape and mould our children into what we think is best. We want to maintain every environment and annalize every scenario to feel like we have considered the best options and followed through with them. However, most of the time, at least for me, this is when God is patiently waiting for you to step aside and let him work. Use wisdom in each decision that you make, but don't over analize and try to control everything so much that you, and your children, miss what God is trying to teach you through it all.
So in the end... I still dont know the answer, but I am just going to pray that I will have the wisdom to answer questions appropriatly and be there to talk when and if they are ready and pray that God will take care of the rest. Pray for us over the next few days.