Anne,
I'll try to tackle some of your questions, although since you didn't say where you were leaving from, that could affect a few of my answers.
First off, if you are traveling overnight, then I would suggest trying to get a bedroom if the cost isn't prohibative. You will be more comfortable in a bedroom than you would be in coach. Depending on just how tall your daughter is, you may be able to consider getting the family room. Just make sure that she's not taller than 4' 9", which is the length of the child beds in that room.
Otherwise you might have to consider a deluxe room, with two of you sharing the lower bunk.
Traveling in a sleeper, while more expensive, does include meals in the dining car. Plus you have access to a shower, something you won't have in coach.
Now for your daughter, have her pack a small backpack (like kids use for school books), with her favorite toys, games, a walkman, and maybe a book or two and things like that. This also gives her something to carry and plan for, making her part of the whole process for planning and arriving at the station. Note: IF you are going in coach, be careful of electronic games where the sound can't be turned off or head phones can't be used.
Next temperatures can vary on the train, especially in coach. The attendants can vary the temperature, however it's very hard to please 80 different people all sitting in one coach. In a bedroom, you do have some control over the temperature, but not total control. Basically you can close or open a vent which allows the air to flow into your room.
If you are in coach, then certainly bring a light jacket at a minimum, if not a light blanket.
Food wise, Amtrak overal has decent food in the diner. Just like any resturant, a lot depends on the cook. Most are pretty good, but I've hit a few that are mediocre. Amtrak has just changed some of its menus as has not yet posted the new ones on the internet. However, you can look at the old ones still by clicking
here. This will at least give you some idea on what to expect, although again expect that some of the choices have changed.
As for timing your meals, by and large the dining car is open for a few hours for each meal. The only time that a meal may have a shortened time would be near the end of the trains journey or right at the start of the journey. Breakfast usually runs from 6:30 to 10:00, lunch 11:30 to 1:30. Dinner typically they will take reservations for. The dining car steward will come around asking people to pick from either two or three seating times, depending on how crowded the train is.
Since you have a special need here, I would approach the dining car steward personally by 3:00 PM or as soon as possible after that time to see if you can't get the time you need. The early seating usually fills up first. If you are on-board for lunch, then ask him at that point about dinner.
Additionally the cafe car is typically available throughout the bulk of the day. One can always buy food here. The cafe will close for short breaks and usually an hour before the train hits the last stop on the run. Otherwise, hours are usually from 6:00 AM to at least 11:00 PM.
As for timeliness, Amtrak doesn't post the average on-time track record for its trains. You can sometimes find a posting of this on the site here. The only other thing that you can do is to visit Amtrak's site. There you can find out the ontime status of the trains currently running, plus those from the last week or so. You could then build your own average from that data. You can find Amtrak's online status
Please also note that even the reports that do get posted here reflect only the endpoint ontime record. The train may have been much later at intermediate stops along the way.
here.
Finally I would suggest checking out
this wonderful Amtrak hints and tips posting from On Track On Line. This will also help to give you some ideas on what to expect and covers many things that I haven't touched upon.
If you have any further questions, please don't hesitate to come back and ask.
Otherwise, have a great trip!