That's great of you, well done for wanting to take your kitty with you! OK, this is gonna be a long one! There are some steps you really should take before starting off, to make your cat and yourself happy to do the journey.
Some say cats can't travel, but when boarding, your cat has to get used to a new environment anyway, so she will be happy you're with them at least!
Cats hate car trips because they are noisy and usually end at the vets! They soon associate the smell of the car to nasty experiences, so Cars are scary things to cats.
There are a few things to do in preparation of the trip:
First, let him explore the car every day for weeks.
Let him loose in the car, don't turn the engine on, and put a litter tray somewhere, and food and water (with appropriate cover sheets to protect the car). Also, don't forget to put some familiar objects around for her, like her fave toys, a pillow from your bed or her own bed. Something that smells like your home.
If you can put the car in a safe place he can access without risk (like a garage, or an enclosed yard) then leave the doors open, otherwise just close the doors and stay with him, reading, chatting or listening to music. Wait for him to settle and fall asleep. Remember to always leave the cat transporter you will use for the trip on the seat, or wherever you keep it usually, WITH THE DOOR OPEN, so that kitty can go in and out of it at leisure.
This will be useful because he needs to get used to the car as a home, a totally safe place where he can sleep and be comfortable with his favourite human/s. Once he knows it well, he won't be so panic stricken to enter it, also during a long journey you will need to stop every few hours to use the tray, so it will come in handy to get him used to the tray being in there.
Once he is comfortable with the car, put him in his transporter crate, that same one that was always in the car with the open door, and then while talking soothingly to her turn the engine on, and go for a ride. Do this as often as possible, and without going to the vet! Just a ride around a few blocks, so that the cat realizes that car does not equal vet, or unpleasant things always.
When you are away you can open the crate's door, but ONLY WHEN THE ENGINE IS OFF, as driving with a cat free in the car can be extrememly dangerous to both of you.
Keep doing these exercises and she might get less terrified, so that her being sick might get better as well, otherwise ask your vet for anti-sickness medicines for cats. Also, don't feed her on the morning of the journey, give her food once she gets there, and either the night before leaving or at least 5 hours before starting off. Leave only fresh water in her clip-on bowl inside her travel crate.
On the day of the trip your cat will enter the car as usual, she might even look forward to it by now, and you will put her in the crate, and stop every 1-2 hours to let her use the toilet, and stretch her 4 legs! The final touch, spray some Feliway travel around the car at the start of the trip, it will ease her mind. You can put 4 drops of Bach flowers Rescue Remedy in the water she'll be drinking, they are flower extracts, so harmless and work wonders in calming the cat down without sedating the poor thing stupid.
Be careful, because once your cat is used to cars she might well get in it whenever she has a chance!
The most IMPORTANT bit is the following:
cats are territorial. They get used to a place and take time to get used to another, usually 4 weeks minimum. This means that if you let your cat roam free in a new place he or she doesn't know, she will get lost. The last thing you want to do is to take your kitty on holiday only to loose her! So, unless you're staying more than 4 weeks on your holiday, or there is a totally escape proof garden, don't let your cat out EVER, without a harness. If she isn't used to a harness she will freak out at being put one on!
Enjoy your holidays with your best friend!
PS: if you think that all this preparations are too much for you, you better have the cat boarded, as 10 hours in a cage for a cat who isn't used to cars will be a nightmare.
PPS: In the trunk they will have not enough air to breathe, for 10 hours!