These questions might be complicated, so if you can even point me in the direction of someone who knows the answers, I'd appreciate it.
My girlfriend and I are both Americans and currently live in San Diego, and we each have a Global Entry card and new USA passports.
We own and operate a business (LLC) that we operate remotely (online and over the phone). I.e. we're self-employed and have money saved up; I think countries won't fear that we lack the financial resources to go back home to the USA.
We want to buy a 1-way ticket to Europe and explore for a while and then relocate back to the USA (probably San Diego again).
We definitely want to visit France and Italy and probably some other countries within the Schengen Area (Belgium, Switzerland, Netherlands, Germany, Greece) and maybe even some other non-Schengen countries (Ireland, Croatia, United Kingdom).
I worry that having no specific plans (timeline, accommodations, travel) will be problematic with immigration officials of various countries.
The EU Immigration Portal says:
"If you are planning a short stay of up to three months in any six-month period of time in an EU country... You will not need a visa to enter the EU if you are from United States of America."
So, if we could commit to spending no more than 90 days in Europe and not travelling to any non-Schengen countries, could we just buy a 1-way flight to France (without any kind of bureaucracy such as applying for a visa)?
What would our border crossing experience in France be like (since we'd only have a short hotel stay reserved and no booked plans to leave yet)?
And if we tried to rent an apartment there for a month or two, would landlords and the government allow it?
Would our travel to other Schengen countries be straightforward and hassle-free if we wanted to live in Italy for a month, for example?
What if we love our time in Europe and want to stay in the EU for more than 90 days (maybe 9 months instead of 3)?
It seems that even a long-stay visa only allows travelling in the Schengen Area "for up 3 months during a six-month period of time".
So if we wanted to live in Europe for 9 months, then 6 of those months would have to be in the country that granted us the long-stay visa?