Ditto the "gunlaws" book. The laws vary so much that you will not get complete advice here. In addition to the "gunlaws" you might consider contacting states that you plan to go through on the next trip.
In past years I did some RVing, but did not go East, not only for the gun laws, but for the traffic. I also tried to avoid time in CA when I could. Best of luck in learning the laws, and have a great time.
Ecclesiastes 12:13 *¶Let us hear the conclusion of the whole matter: Fear God, and keep his commandments: for this is the whole duty of man.
14 *For God shall bring every work into judgment, with every secret thing, whether it be good, or whether it be evil.