Get yourself the "Traveler's Guide to the Firarm Laws of the Fifty States" from the NRA store. It's very informative. Read the How too, first.
Many states do not require you to inform the LEO, but some do by law. I do not give any information to a LEO that is not required. I have considerable respect for them, but, in the end they are the friend of a prosecutor, not yours.
Whatever you are asked, tell the truth and follow Leo's instructions, and be courteous.
"...from my cold dead hands" Charlton Heston & NRA
"He which hath no stomach to this fight,/ Let him depart." Henry V