To get both dogs use to traveling, you should take them on short trips around town, the more trips the better. The more they ride and enoy it the easier it will be. You have lots of time to start training them. This way they will know what to expect, and not be afraid of anything.
I haven't traveled with dogs in a long time, but it sounds like you've thought of everything. Are your dogs microchipped? If not please have them done before you leave. Also be sure they are wearing tags, and the tags and leashed at ALL times, I have read lots of stories about dogs getting lost in traveling, and I would sure hate it to be yours.
I would also go with a doggie seat belt, I think the crate might be too confining in the car. Get meds from the vet for car sickness no need to give it unless needed. At least you'll have it with you. Also if they are prone to being car sick be sure to not feed them in the car and maybe go light on their feedings beforehand. Also make sure you have their vaccines up to date especially the rabies and have proof of everything.
Exercise would be great before having to be in their crates. Remember a tired dog is a good dog.
Another important thing to remember is NEVER leave them unattended in a car parked in the sun. Actually I would never leave them unattended in the car at all, but that's just me.
I hope ya'll have a great trip. Keep a journal, and take lots of pictures. That will be great to have so you can look back on your fun trip.
