Im a young Aussie planning to visit the USA next year. It will be my first time traveling overseas and Ill be by myself, which is scary to think about. Driving myself around is not an option. Ill be relying on buses, trains, taxis, etc. and Im going to have no idea what Im doing. Advice from locals and experienced travellers would be very much appreciated. Not sure if it makes a difference but Ill be visiting for most of May and June.

In particular Im wondering what will be the best way to travel between the northeastern cities (Boston, NYC, Philly and D.C.). A travel agent suggested that I travel between these cities by Amtrak train but when I looked into this it looked like a very expensive option. (More expensive than flying by plane in Australia!) The Amtrak website also seems to indicate that checked baggage is not an option on all trains which could be an issue as Ill have a sizeable piece of luggage with me.

Im doing a guided tour of the national parks that starts and finishes in Vegas, so Ill also need to figure out the most convenient way of getting from Los Angeles to Vegas. I found this "luxury" transfer service for ~$130 AUD on Viator. Im not looking for luxury though.

Im also wondering about the best way to get around in each city, just in general. What is public transport like? Ill be visiting San Francisco, Los Angeles, Las Vegas, Boston, NYC, Philly and D.C.. Given that Im a young woman travelling by myself, what is the safest way for me to get around at night? Taxi? (Ive been told to avoid the Subway at night)

It would be helpful to get some tips from locals as to what traps should be avoided that tourists might typically fall for. Im travelling on a student budget and the Aussie dollar is terrible at the moment, so I dont want to be paying more to get from A to B than I need to.

Thank you in advance for any advice and apologies if these newb questions dont belong here.