It may be possible... but have in mind that Dreamforce is a massive conference, to the point that by now, it's more than likely that every hotel/B&B/AirBnB/etc in San Francisco is either sold out or charging $$$$$....
It's so huge, last year they had a cruise ship where conference attendees stayed because there were not enough hotel rooms...
so... the recommendation would be to have in mind all of this before considering to participate - maybe this one could be for the local fans...
Plus, with it being so close, on top of the hotel charges, airfare will be very high also.