All in one computers are they type with display that has a CD drive, processor, and computer 'all in one' package. While OK for a desktop computer, they are a bit larger than a laptop.
But a laptop is more portable, you can take it with you while out sightseeing, and might be able to pick up a 'free' wi-fi public signal from someplace, and be able to download your e-mails. Or take it to the office, and download them.
Many new laptops also include a camera. I bought one at Best Buy for only about $330, and it included a camera. My niece set up Skype, a free phone service. If you are calling another computer, you can use the camera's to see the person you are talking to!
Check with Best Buy if you have one nearby. THey have branches all over the country, so you can get service in most large cities. . .
Good luck on your travels! I hope that you can find a local RV park. Sometimes they are difficult to find in California. Check moble home parks in your area, and ask about them setting up a place for you for the next couple of months. .
Fred.