Okay so Yig kicked us all over the place and now we face Nyarlathotep who we are actually doing rather better against... well that is to say we know what we are doing! ... ANYWAY this is possibly a stupid question but when one pops out of 'lost in time and space' (it says in the rules you can reappear in Arkam anywhere in the rules) can it be directly onto a gate to close it?.

I imagine not, but it doesn't seem clear....

We are totally addicted and have been playing all day ...how long is a game really supposed to loast?

You can appear in that location, but since you can't close the gate unless you have an explored token, you'd still have to go through usual rigmarole of entering the gate, having other world encounters, and coming back.

Depending on number of players and so forth, most games last three or four hours, unless something goes horribly wrong early on. Things get a lot quicker once everyone is familiar with the strategy and doesn't have to keep checking the rules.