As long as you have a US visa with you, you can also enter Mexico.
Guam is a US Territory, and as such, just like any other US owned soil, a Visa is not required as long as you are a US citizen. Saipan also does not require a Visa to visit.
People from some countries are allowed 30 days without a Visa. Others are allowed 6 month tourist visit with out special Visa. Contact you local US Consulate or visit the US Imigration website for info on your country.
Yes you can, as long as your passport is valid
If you are just going to visit him in the US, all you need is a visit visa (tourist visa) but if you are planning on making your home permanently there with him, he needs to apply for a K-3 spousal visa for you.
No you can get visa only once. Till your visa is valid you can visit multiple times
do danish citizens need a visa to visit Saipan Nothern Marianas
yes but it has to be an American visa.
refer to visa link.com for visa questions
No, a visa is not necessary, as Japan is in the visa waiver program, but that would require an ESTA from you.
As long as you have a proof of your legal stay in the US then you can travel by airplane to another state, but it is preferable to travel with your Visa already there especially when you are traveling by Air.
no