Those Monarch cats look pretty big to me, but size can be deceiving in photos. Anyway, by the looks of them, I would guess that they are 4th or 5th instars now. That means that it won't be long for them before they stop eating and start wandering around inside the enclosure to find a spot to attach to. Generally speaking, the butterfly eggs hatch in 3-5 days, and then they spend "about" 2 weeks as caterpillars and then "about" 2 weeks as chrysalides. You could always take the cats/chrysalides along for your trip. I'm not certain that I am sure about what you are asking in question #2.
Angie

They are so cute! I just LOVE them!
Back in June I received my monarch caterpillar shipment 2 weeks early.

I was literally walking out of the door when the mail man threw a package at my door. It was them! I was not staying home or letting them stay by them selves as that was the first time I was caring for them. I took a huge swamp milkweed and all 11 eggs with me to go camping in Ocean City. They went every where I went.. lol.. No laughing please, I never ever done it before and I really did not want anything happening to my sons birthday present.

Cghcnp, I can't imagine how you transported those caterpillars over hill and dale like that! My hamper is about 2 feet high and a foot and a half wide. Somehow I can't see carrying it on the train to Maryland!

Bandjzmom, I think those cats are 12 days old now after hatching. It seems to me likely they will eclose after Labor Day, If your timetable is correct. I should be okay. My DH will be home, anyway, and I have his Boy Scout pledge that he will to take good care of my babies!
Liz

Oh, well you are fine then if you have a Boy Scout DH to man the ship!! :o)

As of this evening...I'm so happy! One more is very close behind. The last will probably pupate towards the end of next week. With luck, I'll be back in time for the big event. I hope so...I bought Amtrak tickets last night!
Liz

Great shots and awesome job!!
It shouldn't be too long now...