No, you're not buying a handgun; at least according to the BATF info below. This makes all the other questions moot. Maybe just get a nice big walking stick? Enjoy your trip!
ATF Online - Firearms - Frequently Asked Questions - Unlicensed Persons
Q: May aliens legally in the United States buy firearms?
An alien legally in the U.S. may acquire firearms if he has a State of residence. An alien has a State of residence only if he is residing in that State and has resided in a State continuously for at least 90 days prior to the purchase. An alien acquiring firearms from a licensee is required to prove both his identity, by presenting a government-issued photo identification, and his residency with substantiating documentation showing that he has resided in the State continuously for the 90-day period prior to the purchase. Examples of qualifying documentation to prove residency include: utility bills, lease agreements, credit card statements, and pay stubs from the purchaser’s place of employment, if such documents include residential addresses.See also Item 5, “Sales to Aliens in the United States,” in the General Information section of this publication.[18 U.S.C. 921, 922(b)(3), (d) and (g), 27 CFR 478.11 and 478.99(a)]
Q: Are there certain persons who cannot legally receive or possess firearms and/or ammunition?
Yes, a person who —
- Has been convicted in any court of a crime punishable by imprisonment for a term exceeding 1 year;
- Is a fugitive from justice;
- Is an unlawful user of or addicted to any controlled substance;
- Has been adjudicated as a mental defective or has been committed to a mental institution;
- Is an alien illegally or unlawfully in the United States or an alien admitted to the United States under a nonimmigrant visa;
- Has been discharged from the Armed Forces under dishonorable conditions;
- Having been a citizen of the United States, has renounced his or her citizenship;
- Is subject to a court order that restrains the person from harassing, stalking, or threatening an intimate partner or child of such intimate partner; or
- Has been convicted of a misdemeanor crime of domestic violence
- Cannot lawfully receive, possess, ship, or transport a firearm.