US LLC formation for non-US resident

I plan to form an LLC in Delaware. I'm a citizen of an EU country and a resident of another EU country. Now... I manage a website that targets one of these countries and I need to be able to charge advertising fees for long term campaigns.

The question is can a non-US resident alien SMLLC legally operate within the US without registering in any of these EU countries? By switching interchangeably between the two, am I considered to have nexus in any (or both) of these countries? Can I just choose to pay federal income taxes in the US, and, if so, what's the procedure to elect to be taxed by the IRS?

By just getting a virtual office & phone no. would the LLC be considered doing business in the US and require to fill a return with the IRS?

No employees needed for 1 - 1.5 years, but planning to sell a series of monthly subscription services in about 6 months from now, besides these long-term advertising campaigns.

Choosing an SMLLC taxed as a sole proprietorship would require to pay taxes in my home country? Or should I elect to be taxed as a C-Corp, or better incorporate (instead of forming the LLC)?

What would be your setup?

Thanks

Get an attorney and an accountant for this one. Looking for tax advantages in this manner seems very complex and this board is just not going to be able to answer it sufficently.

IMHO things this complex require paying someone that knows this type of scenario. Getting free help on a website does not suffice. After all, how would you know what you get here is correct? You would still have to verify it with a legal entity, plus you wouldn't want to get 'caught ' for something you were ignorant of.

Go the attorney / accountant route

I'm no lawyer, so take this with a grain of salt, but my understanding is that if you're operating in the US you'll probably need to pay taxes in the US on the income you earn. But this all depends too on what your plans are: are the subscriptions being sold in the US?

Also you should be sure to find out what sort of tax treaty your country or countries of residence have with the US, since that will also affect what sorts of taxes you will have to pay.