Travel to Iran (Tehran)

Dear IN community in Iran,

A friend (male) and I are planning to travel to Iran sometimes next year. We are still in an early planning phase, hence not much defined so far.

We have a number of questions which I'd like to ask you:

Is it possible to get around by ourselves or is a travel agency required? If so, can someone recommed one?

Can my friend and I share a hotel room although we are not married or would we need two single rooms each time?

Are there any other restrictions when travelling as an unmarried couple?

Can you suggest places to go, things to see and do?

Any no-gos?

BTW: We may be able to get the visa through his company.

I'm looking forward to your replies,

Sandra